Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Service Pier Extension Project on Naval Base Kitsap Bangor, Washington, 10689-10713 [2018-04857]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 48 (Monday, March 12, 2018)]
[Notices]
[Pages 10689-10713]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-04857]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF870


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Service Pier Extension Project 
on Naval Base Kitsap Bangor, Washington

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals incidental to vibratory and impact 
pile driving associated with proposed construction of the Service Pier 
Extension (SPE) at Naval Base Kitsap Bangor, Washington. 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 
will consider public comments prior to making any final decision on the 
issuance of the requested MMPA authorizations and agency responses will 
be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than April 
11, 2018.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm 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: Rob Pauline, 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: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    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 
authorization is provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill or attempt to harass, hunt, capture, or kill any marine 
mammal.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild (Level A harassment); or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (Level B harassment).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in CE B4 of the Companion Manual for NOAA Administrative Order 216-6A, 
which do not individually or cumulatively have the potential for 
significant impacts on the quality of the human environment and for 
which we have not identified any extraordinary circumstances that would 
preclude this categorical exclusion. Accordingly, NMFS has 
preliminarily determined that the issuance of the proposed IHA 
qualifies to be categorically excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On August 9, 2017 NMFS received a request from the Navy for an IHA 
to take marine mammals incidental to pile driving and removal 
associated with proposed construction of the SPE on Naval Base Kitsap 
Bangor, Washington. The application was deemed adequate and complete by 
NMFS on November 15, 2017.
    The Navy's request is for take by Level B harassment of five marine 
mammal species and Level A harassment of one species. Neither the Navy 
nor NMFS expect serious injury or immortality to result from this 
activity and, therefore, an IHA is appropriate.

[[Page 10690]]

Description of Proposed Activity

Overview

    The Navy is proposing to extend the service pier to provide 
additional berthing capacity and improve associated facilities for 
existing homeported and visiting submarines at Naval Base Kitsap 
Bangor. The project includes impact and vibratory pile driving and 
vibratory pile removal. Sounds resulting from pile driving and removal 
may result in the incidental take of marine mammals by Level A and 
Level B harassment in the form of auditory injury or behavioral 
harassment. Naval Base Kitsap Bangor is located on Hood Canal 
approximately 20 miles (32 kilometers) west of Seattle, Washington. The 
in-water construction period for the proposed action will occur over 12 
months.

Dates and Duration

    The proposed IHA would be effective from October 1, 2018, to 
September 30, 2019 and cover two in-water work windows. Timing 
restrictions would be complied with to avoid conducting activities when 
juvenile salmonids are most likely to be present (February-July). To 
protect Endangered Species Act (ESA)-listed salmonid species, pile 
driving will only be conducted during the designated in-water work 
window between July 16 and January 15. A total of 160 days of in-water 
work will be required during the effective dates of the proposed IHA. 
Approximately 125 days will be required for installation of steel piles 
and will use a combination of vibratory (preferred) and impact methods. 
An estimated 35 days will be required for impact installation of 
concrete piles. Vibratory pile installation and removal may require a 
maximum of 5 hours per day while up to 45 minutes of daily impact 
driving may be required.

Specific Geographic Region

    Naval Base Kitsap Bangor is located north of the community of 
Silverdale in Kitsap County on the Hood Canal (Figure 1-1 in 
application). Hood Canal is a long, narrow, fjord-like basin of western 
Puget Sound. Throughout its 67 mi (108 km) length, the width of the 
canal varies from 1 to 2 mi (1.6 to 3.2 km) and exhibits strong depth/
elevation gradients. The tides in Hood Canal are mixed semidiurnal, 
with one flood and one ebb tidal event with a small to moderate range 
(1 to 6 ft (0.3 to 1.8 m)) and a second flood and second ebb with a 
larger range (8 to 16 ft (2.4 to 4.9 m)) during a 24-hour and 50-minute 
tidal day (URS and SAIC, 1994; Morris et al., 2008).
    The proposed location for the SPE is just north of Carlson Spit and 
south of Keyport/Bangor (KB) Dock (Figure 1-2 in application). Two 
restricted areas are associated with Naval Base Kitsap Bangor, Naval 
Restricted Areas 1 and 2 (33 CFR 334.1220), which are depicted in 
Figure 1-2 in the application relative to the project area.

Detailed Description of Specific Activity

    As part of the proposed action, the Navy proposes to extend the 
existing Service Pier and construct associated support facilities. This 
action is needed to accommodate the proposed relocation of two SEAWOLF 
Class submarines from Naval Base Kitsap Bremerton. The existing Bangor 
waterfront Service Pier will be extended, and associated support 
facilities will be constructed, including a Waterfront Support 
Building, Pier Services and Compressor Building, roadway and utility 
upgrades, a parking lot, and a laydown area. Construction of upland 
facilities will not result in harassment of marine mammals; therefore, 
these activities are not included in the Navy's IHA request and are not 
discussed further.
    The proposed extension of the Service Pier will be approximately 68 
by 520 ft (21 by 158 m) and will require installation of approximately 
203 36-inch (90-centimeter (cm)) diameter steel piles and 50 24-inch 
(60 cm) diameter steel pipe support piles. Approximately 103 18-inch 
(45 cm) square concrete fender piles will also be installed. In 
addition, 27 36-inch (90 cm) diameter steel falsework piles will be 
temporarily installed and subsequently removed. The pier extension will 
extend to the southwest from the south end of the existing Service Pier 
and will parallel Carlson Spit in water depths of 30 to 50 ft (9 to 15 
m) below mean lower low water (MLLW), such that the berthing areas for 
the new submarines will be in water depths of approximately 50 to 85 ft 
(15 to 26 m) below MLLW. A concrete float 150 ft (46 m) long and 15 ft 
(4.6 m) wide will be attached to the south side of the SPE. The 
existing Port Security Barrier (PSB) system will be reconfigured 
slightly to attach to the end of the new pier extension, with 
approximately 540 ft (165 m) removed. Removal and disposal of existing 
PSBs will be implemented as described for the Land-Water Interface 
project (Navy, 2016a). Construction is expected to require one barge 
with a crane, one supply barge, a tugboat, and work skiffs. Concurrent 
driving of separate piles will not occur.
    Construction will be preceded by removal of an existing wave screen 
(including piles) and other existing piles from the Service Pier 
(Figure 1-4 in application). A total of 36 creosote timber piles (19 
18-inch (45 cm) and 17 15-inch (38 cm) piles) will be removed by 
wrapping the piles with a cable or chain and pulling them or using 
vibratory extraction; piles will be cut at the mudline if splitting or 
breakage occurs and they are not able to be pulled. A new wave screen 
will be installed under the SPE (Figure 1-4). This screen will be 
approximately 200 ft (60 m) long and 27 ft (8 m) high (below 20 ft (6 
m) MLLW to above 7 ft (2 m) MLLW), made of concrete or steel, and 
attached to steel support piles for the SPE.
    Pile driving for steel piles will use a combination of vibratory 
and impact driving. Because impact driving of steel piles can produce 
underwater noise levels that have been known to be harmful to fish and 
wildlife, including marine mammals, vibratory driving will be the 
primary method utilized to drive steel piles except when geotechnical 
conditions require use of an impact hammer. An impact hammer will also 
be used to ``proof'' load-bearing piles driven by vibratory methods. 
Driving of the concrete piles will use impact methods only. For impact 
driving, there will be a maximum of 1,600 pile strikes per day. All 
types of in-water work will occur only during the in-water work period.
    Falsework Piles. It is anticipated that 27 36-inch (90 cm) diameter 
steel piles will be temporarily installed. Falsework piles are used to 
temporarily support a construction component in place until 
construction is sufficiently advanced to where the new construction can 
support itself. All falsework piles will be installed using a vibratory 
pile driver only and will be extracted with a vibratory pile driver at 
the conclusion of construction.
    Permanent Piles. As shown in Table 1 permanent piles installed 
include 203 36-inch (90 cm) diameter steel pipe, 50 24-inch (60 cm) 
diameter steel fender, and 103 18-inch (45 cm) diameter concrete piles. 
Driving of the steel support piles will use a combination of vibratory 
(primary) and impact methods and will require up to 125 days of pile 
driving. When impact driving steel pipe piles, a bubble curtain or 
other noise attenuation device would be employed for all pile strikes 
with the possible exception of short periods when the device is turned 
off to test the effectiveness of the noise attenuation device. Driving 
of the concrete piles will use impact methods only, and will require up 
to 35 days of pile driving and would occur for a maximum of 45 minutes 
a day. Vibratory pile driving

[[Page 10691]]

activity in a day will last a maximum of 5 hours, and impact pile 
driving (if required) will last less than 45 minutes for a total of 
less than 5 hours and 45 minutes of pile driving activity in a day. All 
pile driving will be completed in a 12- month period crossing two in-
water work periods.

               Table 1--In-Water Pile Driving Methods, Pile Characteristics, and Driving Durations
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                                                                                    Maximum
                                                   Pile size and                    activity
     SPE project feature            Method             type           Number    duration within    Maximum days
                                                                                 24-hour period
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Pile Removal from Existing     Vibratory.......  15-inch (38 cm)            36  5 hours........  125 days.
 Wave Screen and Pier.                            to 18-inch (45
                                                  cm) creosote-
                                                  treated timber.
Temporary Falsework..........  Vibratory         36-inch (90 cm)            27  5 hours........
                                installation      steel.
                                and removal.
Small Craft Mooring and        Vibratory, with   24-inch (60 cm)            50  5 hours          ...............
 Dolphins.                      proofing.         steel.                         vibratory and
                                                                                 up to 45
                                                                                 minutes impact.
Pier and Wave Screen           Vibratory, with   36-inch (90 cm)           203  5 hours
 Attachment.                    proofing.         steel.                         vibratory and
                                                                                 up to 45
                                                                                 minutes impact.
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Fender Piles.................  Impact..........  18-inch (45 cm)           103  0.75 hour......  35 days
                                                  concrete.                                       (following
                                                                                                  completion of
                                                                                                  timber removal
                                                                                                  and steel pile
                                                                                                  installation).
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Key: cm = centimeters; SPE = Service Pier Extension.

    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 (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical 
and behavioral descriptions) may be found on NMFS's website 
(www.nmfs.noaa.gov/pr/species/mammals/).
    Table 2 lists all species with expected potential for occurrence in 
Hood Canal and summarizes information related to the population or 
stock, including regulatory status under the MMPA and ESA and potential 
biological removal (PBR), where known. An expected potential was 
defined as species with any regular occurrence in Hood Canal since 
1995. Note that while not observed on a consistent basis, west coast 
transient killer whales have been recorded intermittently in Hood Canal 
with the most recent sightings occurring in 2016 as described below. 
They have also been recorded remaining in the area for extended 
periods. As such, they have been listed as one of the species for which 
authorized take has been requested. For taxonomy, we follow Committee 
on Taxonomy (2017). 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. 
All managed stocks in this region are assessed in NMFS's U.S. Pacific 
Marine Mammal SARs (Carretta et al., 2016) or Alaska Marine Mammal SARs 
(Muto et al., 2016). All values presented in Table 2 are the most 
recent available at the time of publication and are available in the 
2016 SARs (Carretta et al., 2016, Muto et al., 2016) (available online 
at: https://www.nmfs.noaa.gov/pr/sars/species.htm).

                                                      Table 2--Species Proposed for Authorized Take
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                                                                                                ESA/ MMPA     Stock abundance (CV,
                                                                                                 status;        Nmin, most recent              Annual M/
              Species                  Scientific name                  Stock                 strategic  (Y/    abundance survey)      PBR       SI \3\
                                                                                                  N) \1\               \2\
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                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Killer whale..................  Orcinus orca........  West coast transient.............  -; N             243 (n/a; 243, 2009)        2.4          0
                                                                                                               \4\.
Family Phocoenidae (porpoises):
    Harbor porpoise...............  Phocoena phocoena     Washington inland waters.........  -; N             11,233 (0.37; 8,308;         66      >=7.2
                                     vomerina.                                                                 2015).
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[[Page 10692]]

 
                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    California sea lion...........  Zalophus              U.S..............................  -; N             296,750 (n/a;             9,200        389
                                     californianus.                                                            153,337; 2011).
    Steller sea lion..............  Eumetopias jubatus    Eastern U.S......................  -; N             41,638 (n/a; 41,638;      2,498        108
                                     monteriensis.                                                             2015).
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Family Phocidae (earless seals):
    Harbor seal...................  Phoca vitulina        Hood Canal.......................  -; N             1,088 (0.15; unk;           unk        0.2
                                     richardii.                                                                1999) \4\.
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\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: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Abundance estimates for these stocks are greater than eight years old and are therefore not considered current. PBR is considered undetermined for
  these stocks, as there is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates,
  as these represent the best available information for use in this document.

    The following species have been sighted in Hood Canal but are not 
likely to be found in the activity area and therefore are not analyzed 
for noise exposure. Humpback whales (Megaptera novaeangliae) have been 
detected year-round in small numbers in Puget Sound; in Hood Canal, 
after an absence of sightings for over 15 years, an individual was seen 
over a 1-week period in early 2012, with additional sightings in 2015 
and 2016 (Orca Network, 2016). Because these sightings are exceptions 
to the normal occurrence of the species in Washington inland waters, 
the species is not included in the analysis in this application. Gray 
whales (Eschrichtius robustus) have been infrequently documented in 
Hood Canal waters over the past decade. These sightings are an 
exception to the normal seasonal occurrence of gray whales in Puget 
Sound feeding areas. Because gray whales are unlikely to be present in 
Hood Canal, the species is not included in this analysis. The Southern 
Resident killer whale stock is resident to the inland waters of 
Washington State and British Columbia; however, it has not been seen in 
Hood Canal in over 20 years and was therefore excluded from further 
analysis. Dall's porpoise (Phocoenoides dalli) has only been documented 
once in Hood Canal and is not included in the analysis.

Killer Whale, West Coast Transient Stock

    Among the genetically distinct assemblages of killer whales in the 
northeastern Pacific, the West Coast Transient stock, which occurs from 
California to southeastern Alaska, is one of two stocks that may occur 
in Puget Sound. The other is the Southern Resident killer whale 
population, which has not been detected in Hood Canal since 1995.
    The geographical range of the West Coast Transient stock of killer 
whales includes waters from California through southeastern Alaska with 
a preference for coastal waters of southern Alaska and British Columbia 
(Krahn et al., 2002). Transient killer whales in the Pacific Northwest 
spend most of their time along the outer coast of British Columbia and 
Washington, but visit inland waters in search of harbor seals, sea 
lions, and other prey. Some studies have shown seasonal trends: Morton 
(1990) found bimodal peaks in occurrence during the spring (March) and 
fall (September to November) on the central coast of British Columbia, 
and Baird and Dill (1995) noted variability in occurrence and behavior 
seasonally and between pods with an increase in sightings near harbor 
seal haulouts off southern Vancouver Island during August and 
September--the peak period for weaning through post-weaning of harbor 
seal pups. More recently (2004-2010), another bimodal trend was 
detected with transient killer whales occurring most frequently in 
Washington inland waters in April-May and August-September (Houghton et 
al., 2015). However, transient killer whales may occur in inland waters 
in any month (Orca Network, 2015), with their habitat use from one day 
to the next being highly unpredictable. These changes in use are likely 
related to their stealthy predation behaviors and reduce the chances of 
detection by their various prey species within the inland waters.
    There are few data to describe the transient killer whale habitat 
use within Hood Canal. Killer whales were historically documented in 
Hood Canal by sound recordings in 1958 (Ford, 1991), a photograph from 
1973, sound recordings in 1995 (Unger, 1997), and also anecdotal 
accounts of historical use. More recently, there have been sightings 
data ranging from intermittent observations of one or two animals, to 
the lengthy stays that were recorded in 2003 of 11 transients that 
remained for nearly 2 months (59 days), and in 2005 of a group of six 
that were sighted over a nearly 4-month period. In 2005, transients 
were documented in the region for a total of 172 days between January 
and July (London, 2006). There is about a 10-year data gap for Hood 
Canal transient killer whale use with the sightings reported to the 
Orca Network in March 2016, when there were sightings over 2 days. 
Following this, there was a report from 1 day in April 2016 and 8 days 
in May 2016, with whales in Dabob Bay at least one of the days (Orca 
Network, 2016). As the sightings in early 2016 were discontinuous, it 
is likely that the whales were using Hood Canal as part of a larger 
area moving in and out of Hood Canal. It is not known how large an area 
these animals were using; it is also unknown if these sightings were 
all of the same group of transient killer whales, or if animals were 
using the same areas. However, the temporally discontinuous data 
suggest a high degree of variability in the habitat use

[[Page 10693]]

and localized relative abundances of transient killer whales in Hood 
Canal. It is also likely that longer periods of more continuous 
sightings are anomalous, and that the usual use of Hood Canal reflects 
the typical transient killer whale behavior of short-term occupancy for 
foraging in a small localized area, then dispersing to other parts of 
their range.
    West Coast Transient killer whales most often travel in small pods 
of up to four individuals (Baird and Dill, 1996). From 2004-2010 in the 
Salish Sea, the most frequently observed group size was four whales 
(Houghton et al., 2015). The most commonly observed group size in Puget 
Sound through South Puget Sound and north to Skagit Bay from 2004 to 
2010 was six whales (mode = 6, mean = 6.88) (Navy, 2017).

Harbor Porpoise

    NMFS conservatively recognizes two stocks in Washington waters: The 
Oregon/Washington Coast stock and the Washington Inland Waters stock 
(Carretta et al., 2013). Individuals from the Washington Inland Waters 
stock are expected to occur in Puget Sound.
    In Washington Inland waters, harbor porpoise are known to occur in 
the Strait of Juan de Fuca and the San Juan Island area year-round 
(Calambokidis and Baird, 1994; Osmek et al., 1996; Carretta et al., 
2012). Harbor porpoises were historically one of the most commonly 
observed marine mammals in Puget Sound (Scheffer and Slipp, 1948); 
however, there was a significant decline in sightings beginning in the 
1940s (Everitt et al., 1979; Calambokidis et al., 1992). Only a few 
sightings were reported between the 1970s and 1980s (Calambokidis et 
al., 1992; Osmek et al., 1996; Suryan and Harvey, 1998), and no harbor 
porpoise sightings were recorded during multiple ship and aerial 
surveys conducted in Puget Sound (including Hood Canal) in 1991 and 
1994 (Calambokidis et al., 1992; Osmek et al., 1996). Incidental 
sightings of marine mammals during aerial bird surveys conducted as 
part of the Puget Sound Ambient Monitoring Program (PSAMP) detected few 
harbor porpoises in Puget Sound between 1992 and 1999 (Nysewander et 
al., 2005). However, these sightings may have been negatively biased 
due to the low elevation of the plane, which may have caused an 
avoidance behavior. Since 1999, PSAMP data, stranding data, and aerial 
surveys conducted from 2013 to 2015 documented increasing numbers of 
harbor porpoise in Puget Sound (Nysewander, 2005; WDFW, 2008; Jeffries, 
2013; Jefferson et al., 2016).
    Sightings in Hood Canal north of the Hood Canal Bridge have 
increased in recent years (Navy 2017). During line transect vessel 
surveys conducted in the Hood Canal in 2011 for the TPP near Naval Base 
Kitsap Bangor and Dabob Bay (HDR Inc., 2012), an average of six harbor 
porpoises were sighted per day in the deeper waters. Group sizes ranged 
from 1 to 10 individuals (HDR Inc., 2012). Aerial surveys conducted 
throughout 2013 to 2015 in Puget Sound indicated density in Puget Sound 
was 0.91 individuals/square kilometers (km\2\)) (95% CI = 0.72-1.10, 
all seasons pooled) and density in Hood Canal was 0.47/km\2\ (95% CI = 
0.29-0.75, all seasons pooled) (Jefferson et al., 2016). Mean group 
size of harbor porpoises in Puget Sound in the 2013-2015 surveys was 
1.7 in Hood Canal.

Steller Sea Lion

    In the North Pacific, NMFS has designated two Steller sea lion 
stocks: (1) The western U.S. stock consisting of populations at and 
west of Cape Suckling, Alaska (144 degrees West longitude); and (2) the 
Eastern U.S. stock, consisting of populations east of Cape Suckling, 
Alaska. The western U.S. stock is listed as depleted under the MMPA and 
endangered under the ESA. Although there is evidence of mixing between 
the two stocks (Jemison et al., 2013), animals from the western U.S. 
stock are not present in Puget Sound. Individuals that occur in Puget 
Sound are of the Eastern Distinct Population Segment (Allen and 
Angliss, 2013). The Eastern Distinct Population Segment (stock) was 
removed from listing under the ESA in 2013 because it was stable or 
increasing throughout the northern portion of its range (Southeast 
Alaska and British Columbia) and stable or increasing slowly in the 
central portion of its range (Oregon through northern California) (78 
FR 66140; NMFS, 2012a).
    The eastern stock of Steller sea lions is found along the coasts of 
southeast Alaska to northern California where they occur at rookeries 
and numerous haulout locations along the coastline (Jeffries et al., 
2000; Scordino, 2006). Along the northern Washington coast, up to 25 
pups are born annually (Jeffries, 2013). Male Steller sea lions often 
disperse widely outside of the breeding season from breeding rookeries 
in northern California (St. George Reef) and southern Oregon (Rogue 
Reef) (Scordino, 2006; Wright et al., 2010). Based on mark recapture 
sighting studies, males migrate back into these Oregon and California 
locations from winter feeding areas in Washington, British Columbia, 
and Alaska (Scordino, 2006).
    In Washington, Steller sea lions use haulout sites primarily along 
the outer coast from the Columbia River to Cape Flattery, as well as 
along the Vancouver Island side of the Strait of Juan de Fuca (Jeffries 
et al., 2000). A major winter haulout is located in the Strait of Juan 
de Fuca at Race Rocks, British Columbia, Canada (Canadian side of the 
Strait of Juan de Fuca) (Edgell and Demarchi, 2012). Numbers vary 
seasonally in Washington, with peak numbers present during the fall and 
winter months and a decline in the summer months that corresponds to 
the breeding season at coastal rookeries (approximately late May to 
early June) (Jeffries et al., 2000). In Puget Sound, Jeffries (Navy 
2017) identified five winter haulout sites used by adult and subadult 
(immature or pre-breeding animals) Steller sea lions, ranging from 
immediately south of Port Townsend (near Admiralty Inlet) to Olympia in 
southern Puget Sound (Figure 4-1). Numbers of animals observed at these 
sites ranged from a few to less than 100 (Navy 2017). In addition, 
Steller sea lions (one to two animals have been observed) 
opportunistically haul out on various navigational buoys in Admiralty 
Inlet south through southern Puget Sound near Olympia (Navy 2017).
    Surveys at Naval Base Kitsap Bangor indicate Steller sea lions 
begin arriving in September and depart by the end of May (Navy, 2016b)

California Sea Lion

    NMFS has defined one stock for California sea lions (U.S. Stock), 
with five genetically distinct geographic populations: (1) Pacific 
Temperate, (2) Pacific Subtropical, (3) Southern Gulf of California, 
(4) Central Gulf of California, and (5) Northern Gulf of California. 
The Pacific Temperate population includes rookeries within U.S. waters 
and the Coronados Islands just south of the U.S./Mexico border. Animals 
from the Pacific Temperate population range north into Canadian waters, 
and movement of animals between U.S. waters and Baja California waters 
has been documented (Carretta et al., 2013).
    During the summer, California sea lions breed on islands from the 
Gulf of California to the Channel Islands and seldom travel more than 
about 31 mi (50 km) from the islands. The primary rookeries are located 
on the California Channel Islands of San Miguel, San Nicolas, Santa 
Barbara, and San Clemente. Their distribution shifts to the northwest 
in fall and to the southeast during winter and spring, probably in 
response to changes in prey availability. In the nonbreeding season, 
adult and subadult males migrate

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northward along the coast to central and northern California, Oregon, 
Washington, and Vancouver Island, and return south in the spring. They 
are occasionally sighted hundreds of miles offshore. Primarily male 
California sea lions migrate into northwest waters with most adult 
females with pups remaining in waters near their breeding rookeries off 
the coasts of California and Mexico. Females and juveniles tend to stay 
closer to the rookeries. California sea lions also enter bays, harbors, 
and river mouths and often haul out on man-made structures such as 
piers, jetties, offshore buoys, and oil platforms.
    Jeffries et al. (2000) and Jeffries (Navy 2017) identified 
dedicated, regular haulouts used by adult and subadult California sea 
lions in Washington inland waters (Figure 4-1). Main haulouts occur at 
Naval Base Kitsap Bangor, Naval Base Kitsap Bremerton, and Naval 
Station (NAVSTA) Everett, as well as in Rich Passage near Manchester, 
Seattle (Shilshole Bay), south Puget Sound (Commencement Bay, Budd 
Inlet), and numerous navigation buoys south of Whidbey Island to 
Olympia in south Puget Sound (Jeffries et al., 2000) (Figure 4-1). Race 
Rocks, British Columbia, Canada (Canadian side of the Strait of Juan de 
Fuca) has been identified as a major winter haulout for California sea 
lions (Edgell and Demarchi, 2012).
    California sea lions are typically present most of the year except 
for mid-June through July in Washington inland waters, with peak 
abundance numbers between October and May (NMFS, 1997; Jeffries et al., 
2000). California sea lions would be expected to forage within the 
area, following local prey availability. During summer months and 
associated breeding periods, the inland waters would not be considered 
a high-use area by California sea lions, as they would be returning to 
rookeries in California waters. However, California sea lions have been 
documented during shore-based surveys at Naval Base Kitsap Bangor in 
Hood Canal since 2008 in all survey months, with as many as 122 
individuals observed at one time (November 2013) hauled out on 
submarines at Delta Pier and on PSB floats (Navy, 2016b, Appendix A). 
Relatively few individuals (< nine sighted per survey) were present 
during these surveys from June through August.

Harbor Seal

    Three harbor seal stocks occur in Washington's inland waters:
     Hood Canal;
     Northern Inland Waters; and
     Southern Puget Sound stocks.
    Based on radiotelemetry results, interchange between inland and 
coastal stocks is unlikely (Jeffries et al., 2003).
    Harbor seals are a coastal species, rarely found more than 12 mi 
(19 km) from shore, and frequently occupy bays, estuaries, and inlets 
(Baird, 2001). Individual seals have been observed several miles 
upstream in coastal rivers (Baird, 2001). Ideal harbor seal habitat 
includes haulout sites, shelter during the breeding periods, and 
sufficient food (Bj[oslash]rge, 2002). Haulout areas can include 
intertidal and subtidal rock outcrops, sandbars, sandy beaches, peat 
banks in salt marshes, and man-made structures such as log booms, 
docks, and recreational floats (Wilson, 1978; Prescott, 1982; Schneider 
and Payne, 1983, Gilbert and Guldager, 1998; Jeffries et al., 2000; 
Lambourn et al., 2010). Harbor seals do not make extensive pelagic 
migrations, though some long distance movement of tagged animals in 
Alaska (108 mi (174 km)) and along the U.S. west coast (up to 342 mi 
(550 km)) have been recorded (Brown and Mate, 1983; Womble and Gende, 
2013). Harbor seals have also displayed strong fidelity to haulout 
sites.
    Harbor seals are the most common, widely distributed marine mammal 
found in Washington marine waters and are frequently observed in the 
nearshore marine environment. They occur year-round and breed in 
Washington. Numerous harbor seal haulouts occur in Washington inland 
waters. Numbers of individuals at haulouts range from a few to between 
100 and 500 individuals (Jeffries et al., 2000).
    Harbor seals are expected to occur year-round at Naval Base Kitsap 
Bangor. In Hood Canal, where Naval Base Kitsap Bangor is located, known 
haulouts occur on the west side of Hood Canal at the mouth of the 
Dosewallips River and on the western and northern shorelines in Dabob 
Bay, located approximately 8.1 miles away from the Navy's installation 
(Figure 4-1). Vessel-based surveys conducted from 2007 to 2010 at Naval 
Base Kitsap Bangor observed harbor seals in every month of surveys 
(Agness and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011). Harbor 
seals were routinely seen during marine mammal monitoring for two 
construction projects, the Test Pile Project and EHW-2 construction 
projects (HDR Inc., 2012; Hart Crowser, 2013, 2014, 2015). Small 
numbers of harbor seals have been documented hauling out on the PSB 
floats, wavescreen at Carderock Pier, buoys, barges, marine vessels, 
and logs (Agness and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011; 
Navy, 2016b) and on man-made floating structures near KB Dock and Delta 
Pier. Incidental surveys by a Navy biologist in August and September 
2016 recorded as many as 28 harbor seals hauled out under Marginal 
Wharf or swimming in adjacent waters. On two occasions, four to six 
individuals were observed hauled out near Delta Pier. The repeated 
sightings of harbor seals in this area suggest a high degree of 
tolerance by these individuals for the anthropogenic activity 
associated with Naval Base Kitsap Bangor. It is also likely that these 
are sightings of the same individuals, rather than different animals 
being observed at the same locations.
    Past IHA applications for Naval Base Kitsap Bangor indicated a few 
observations of harbor seal births or neonates. In 2014, the Navy's 
knowledge of harbor seal births increased due to increased pinniped 
surveys on the waterfront and increased contact with waterfront 
personnel who have had lengthy careers at Bangor (Navy, 2016b). Known 
harbor seal births include one on the Carderock wave screen in August 
2011; at least one on a small 10 x 10 ft (3 x 3 m) floating dock at 
EHW-2 in fall 2013, as reported by EHW-2 construction crew; and 
afterbirth on a float at Magnetic Silencing Facility with an unknown 
date. In addition, Navy biologists learned that harbor seal pupping has 
occurred on a section of the Service Pier since approximately 2001, 
according to the Port Operations vessel crews. Harbor seal mother and 
pup sets were observed in 2014 hauled out on the Carderock wavescreen 
and swimming in nearby waters, and swimming in the vicinity of Delta 
Pier (Navy, 2016b).

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

[[Page 10695]]

cetaceans). Subsequently, NMFS (2016) 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. The functional groups and the associated frequencies 
are indicated below (note that these frequency ranges correspond to the 
range for the composite group, with the entire range not necessarily 
reflecting the capabilities of every species within that group):
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 hertz (Hz) and 160 kilohertz (kHz);
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): Generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz;
     Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz; 
and
     Pinnipeds in water; Otariidae (eared seals): Generalized 
hearing is estimated to occur between 60 Hz and 39 kHz.
    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 (2016) for a review of available information. 
Five marine mammal species (two cetacean and three pinniped (two 
otariid and 1 phocid) species) have the reasonable potential to co-
occur with the proposed survey activities. Of the cetacean species that 
may be present, killer whales are classified as mid-frequency cetaceans 
and harbor porpoises are classified as high-frequency cetaceans.

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 by Incidental Harassment'' 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 by Incidental 
Harassment'' 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.

Description of Sound Sources

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds and attenuate (decrease) more 
rapidly in shallower water. Amplitude is the height of the sound 
pressure wave or the `loudness' of a sound and is typically measured 
using the dB scale. A dB is the ratio between a measured pressure (with 
sound) and a reference pressure (sound at a constant pressure, 
established by scientific standards). It is a logarithmic unit that 
accounts for large variations in amplitude; therefore, relatively small 
changes in dB ratings correspond to large changes in sound pressure. 
When referring to sound pressure levels (SPLs; the sound force per unit 
area), sound is referenced in the context of underwater sound pressure 
to 1 micro pascal ([mu]Pa). One pascal is the pressure resulting from a 
force of one newton exerted over an area of one square meter. The 
source level (SL) represents the sound level at a distance of 1 m from 
the source (referenced to 1 [mu]Pa). The received level is the sound 
level at the listener's position. Note that all underwater sound levels 
in this document are referenced to a pressure of 1 [micro]Pa and all 
airborne sound levels in this document are referenced to a pressure of 
20 [micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Rms is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick, 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al.,1995), and the sound level of 
a region is defined by the total acoustical energy being generated by 
known and unknown sources. These sources may include physical (e.g., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). In general, ambient sound levels tend to increase 
with increasing wind speed and wave height. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km from shore showing an increase of 10 dB in the 100 to 700 Hz band 
during heavy surf conditions;
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times;
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological

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contributions is from approximately 12 Hz to over 100 kHz; and
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly (Richardson et al., 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and vibratory pile 
extraction. The sounds produced by these activities fall into one of 
two general sound types: Pulsed and non-pulsed (defined in the 
following paragraphs). 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). Please see Southall et al., (2007) for an in-
depth discussion of these concepts.
    Pulsed sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; ISO, 2003) and occur either as isolated 
events or repeated in some succession. Pulsed sounds are all 
characterized by a relatively rapid rise from ambient pressure to a 
maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or non-continuous (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling, vibratory 
pile driving, and active sonar systems (such as those used by the U.S. 
Navy). The duration of such sounds, as received at a distance, can be 
greatly extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper 2005). Vibratory 
hammers install piles by vibrating them and allowing the weight of the 
hammer to push them into the sediment. Vibratory hammers produce 
significantly less sound than impact hammers. Peak SPLs may be 180 dB 
or greater, but are generally 10 to 20 dB lower than SPLs generated 
during impact pile driving of the same-sized pile (Oestman et al., 
2009). Rise time is slower, reducing the probability and severity of 
injury, and sound energy is distributed over a greater amount of time 
(Nedwell and Edwards 2002).

Acoustic Impacts

    Please refer to the information given previously (Description of 
Sound Sources) regarding sound, characteristics of sound types, and 
metrics used in this document. Anthropogenic sounds cover a broad range 
of frequencies and sound levels and can have a range of highly variable 
impacts on marine life, from none or minor to potentially severe 
responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: Temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). The degree of 
effect is intrinsically related to the signal characteristics, received 
level, distance from the source, and duration of the sound exposure. In 
general, sudden, high level sounds can cause hearing loss, as can 
longer exposures to lower level sounds. Temporary or permanent loss of 
hearing will occur almost exclusively for noise within an animal's 
hearing range. In this section, we first describe specific 
manifestations of acoustic effects before providing discussion specific 
to the proposed construction activities in the next section.
    Permanent Threshold Shift--Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt 
et al., 2000; Finneran et al., 2002, 2005). TS can be permanent (PTS), 
in which case the loss of hearing sensitivity is not fully recoverable, 
or temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Repeated sound exposure that 
leads to TTS could cause PTS. In severe cases of PTS, there can be 
total or partial deafness, while in most cases the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter 
1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above (a 40-dB threshold shift approximates PTS 
onset; e.g., Kryter et al., 1966; Miller 1974) that inducing mild TTS 
(a 6-dB threshold shift approximates TTS onset; e.g., Southall et al., 
2007). Based

[[Page 10697]]

on data from terrestrial mammals, a precautionary assumption is that 
the PTS thresholds for impulse sounds (such as impact pile driving 
pulses as received close to the source) are at least six dB higher than 
the TTS threshold on a peak-pressure basis and PTS cumulative sound 
exposure level thresholds are 15 to 20 dB higher than TTS cumulative 
sound exposure level thresholds (Southall et al., 2007).
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to sound (Kryter 1985). While 
experiencing TTS, the hearing threshold rises, and a sound must be at a 
higher level in order to be heard. In terrestrial and marine mammals, 
TTS can last from minutes or hours to days (in cases of strong TTS). In 
many cases, hearing sensitivity recovers rapidly after exposure to the 
sound ends.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. 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. 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 occurs during a time 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.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)); and three species of pinnipeds (northern elephant 
seal (Mirounga angustirostris), harbor seal, and California sea lion 
exposed to a limited number of sound sources (i.e., mostly tones and 
octave-band noise) in laboratory settings (e.g., Finneran et al., 2002; 
Nachtigall et al., 2004; Kastak et al., 2005; Lucke et al., 2009; Popov 
et al., 2011). In general, harbor seals (Kastak et al., 2005; Kastelein 
et al., 2012a) and harbor porpoises (Lucke et al., 2009; Kastelein et 
al., 2012b) have a lower TTS onset than other measured pinniped or 
cetacean species. Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. There 
are no data 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), and Finneran (2015).
    Behavioral Effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al., 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Appendices B-C of Southall et al. (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    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, 
2003). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely

[[Page 10698]]

contributing factors to differences in response in any given 
circumstance (e.g., Croll et al., 2001; Nowacek et al., 2004; Madsen et 
al., 2006; Yazvenko et al., 2007). A determination of whether foraging 
disruptions incur fitness consequences would require information on or 
estimates of the energetic requirements of the affected individuals and 
the relationship between prey availability, foraging effort and 
success, and the life history stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007b). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient

[[Page 10699]]

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).
    Auditory 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., 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.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Non-Auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance effects, and other types of organ 
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. In general, little is known about 
the potential for pile driving to cause auditory impairment or other 
physical effects in marine mammals. Available data suggest that such 
effects, if they occur at all, would presumably be limited to short 
distances from the sound source, where SLs are much higher, and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007) or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. However, the proposed 
activities do not involve the use of devices such as explosives or mid-
frequency active sonar that are associated with these types of effects. 
Therefore, non-auditory physiological impacts to marine mammals are 
considered unlikely.

Underwater Acoustic Effects From the Proposed Activities

    Potential Effects of Pile Driving Sound--The effects of sounds from 
pile driving might include one or more of the following: Temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, and behavioral disturbance (Richardson et al., 1995; Gordon et 
al., 2003; Nowacek et al., 2007; Southall et al., 2007). The effects of 
pile driving on marine mammals are dependent on several factors, 
including the type and depth of the animal; the pile size and type, and 
the intensity and duration of the pile driving sound; the substrate; 
the standoff distance between the pile and the animal; and the sound 
propagation properties of the environment. Impacts to marine mammals 
from pile driving activities are expected to result primarily from 
acoustic pathways. As such, the degree of effect is intrinsically 
related to the frequency, received level, and duration of the sound 
exposure, which are in turn influenced by the distance between the 
animal and the source. The further away from the source, the less 
intense the exposure should be. The substrate and depth of the habitat 
affect the sound propagation properties of the environment. In 
addition, substrates that are soft (e.g.,

[[Page 10700]]

sand) would absorb or attenuate the sound more readily than hard 
substrates (e.g., rock) which may reflect the acoustic wave. Soft 
porous substrates would also likely require less time to drive the 
pile, and possibly less forceful equipment, which would ultimately 
decrease the intensity of the acoustic source.
    Hearing Impairment and Other Physical Effects--Marine mammals 
exposed to high intensity sound repeatedly or for prolonged periods can 
experience hearing threshold shifts. PTS constitutes injury, but TTS 
does not (Southall et al., 2007). Based on the best scientific 
information available, the SPLs for the proposed construction 
activities may exceed the thresholds that could cause TTS or the onset 
of PTS based on NMFS' new acoustic guidance (NMFS, 2016).
    Disturbance Reactions--Responses to continuous sound, such as 
vibratory pile installation, have not been documented as well as 
responses to pulsed sounds. With both types of pile driving, it is 
likely that the onset of pile driving could result in temporary, short 
term changes in an animal's typical behavior and/or avoidance of the 
affected area. Specific behavioral changes that may result from this 
proposed project include changing durations of surfacing and dives, 
moving direction and/or speed; 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); 
and avoidance of areas where sound sources are located. If a marine 
mammal responds to a stimulus by changing its behavior (e.g., through 
relatively minor changes in locomotion direction/speed or vocalization 
behavior), the response may or may not constitute taking at the 
individual level, and is unlikely to affect the stock or the species as 
a whole. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, potential 
impacts on the stock or species could potentially be significant if 
growth, survival and reproduction are affected (e.g., Lusseau and 
Bejder, 2007; Weilgart, 2007). Note that the significance of many of 
these behavioral disturbances is difficult to predict, especially if 
the detected disturbances appear minor.
    Local observations of marine mammals at Naval Base Kitsap Bangor 
during a Test Pile Project (TPP) concluded that pinniped (harbor seal 
and California sea lion) foraging behaviors decreased slightly during 
construction periods involving impact and vibratory pile driving, and 
both pinnipeds and harbor porpoise were more likely to change direction 
while traveling during construction (HDR Inc., 2012). Pinnipeds were 
more likely to dive and sink when closer to pile driving activity, and 
a greater variety of other behaviors were observed with increasing 
distance from pile driving. Relatively few observations of cetacean 
behaviors were obtained during pile driving. Most harbor porpoises were 
observed swimming or traveling through the project area, and no obvious 
behavioral changes were associated with pile driving.
    Three years of marine mammal monitoring were conducted to support 
vibratory and impact pile driving for the construction of Explosives 
Handling Wharf #2 (EHW-2) at Kitsap Bangor (Hart Crowser, 2013; 2014; 
2015). Over the 3 years of monitoring, harbor seals, California sea 
lions, and Steller sea lions were detected within the shutdown and 
behavioral disturbance zones (Primary Surveys). Results from monitoring 
varied slightly year to year, but in general, it has been found that 
marine mammals were equally observed moving away from (or swimming 
parallel to) the pile or having no motion during vibratory pile 
driving. During impact driving, animals were most frequently observed 
moving away (or moving parallel to) or having no relative motion to the 
pile (Hart Crowser, 2013; 2014; 2015). Harbor porpoises' predominant 
behavior during construction (vibratory pile driving) was swimming or 
traveling through the project area. During pre-construction monitoring, 
marine mammal observers also reported harbor porpoise foraging. Marine 
mammal observers did not detect adverse reactions to TPP or EHW-2 
construction activities consistent with distress, injury, or high speed 
withdrawal from the area, nor did they report obvious changes in less 
acute behaviors.
    Auditory Masking--Natural and artificial sounds can disrupt 
behavior by masking. Given that the energy distribution of pile driving 
covers a broad frequency spectrum, sound from these sources would 
likely be within the audible range of marine mammals present in the 
project area. Impact pile driving activity is relatively short-term, 
and mostly for proofing, with rapid pulses occurring for only a few 
minutes per pile. The probability for impact pile driving resulting 
from this proposed action masking acoustic signals important to the 
behavior and survival of marine mammal species is low. Vibratory pile 
driving is also relatively short-term. It is possible that vibratory 
pile driving resulting from this proposed action may mask acoustic 
signals important to the behavior and survival of marine mammal 
species, but the short-term duration and limited affected area would 
result in insignificant impacts from masking. Any masking event that 
could possibly rise to Level B harassment under the MMPA would occur 
concurrently within the zones of behavioral harassment already 
estimated for vibratory and impact pile driving, and which have already 
been taken into account in the exposure analysis.
    Airborne Acoustic Effects From the Proposed Activities--Pinnipeds 
that occur near the project site could be exposed to airborne sounds 
associated with pile driving 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 will 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 heads above water. 
Most likely, airborne sound would cause behavioral responses similar to 
those discussed above in relation to underwater sound. However, these 
animals would previously have been ``taken'' as a result of exposure to 
underwater sound above the behavioral harassment thresholds, which are 
in all cases larger than those associated with airborne sound. Thus, 
the behavioral harassment of these animals is already accounted for in 
these estimates of potential take. Multiple instances of exposure to 
sound above NMFS' thresholds for behavioral harassment are not believed 
to result in increased behavioral disturbance, in either nature or 
intensity of disturbance reaction. 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.
    Potential Pile Driving Effects on Prey--Construction activities 
would produce continuous (i.e., vibratory pile driving) sounds and 
pulsed (i.e., impact driving) sounds. Fish react to sounds that are 
especially strong and/or intermittent low-frequency sounds. Short 
duration, sharp sounds can cause overt or subtle changes in fish 
behavior and local distribution. Hastings and Popper (2005) identified 
several studies

[[Page 10701]]

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). Sound pulses at received levels of 160 dB may 
cause subtle changes in fish behavior. SPLs of 180 dB may cause 
noticeable changes in behavior (Pearson et al., 1992; Skalski et al., 
1992). SPLs of sufficient strength have been known to cause injury to 
fish and fish mortality.
    The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance within an 
undetermined portion of the affected area. The duration of fish 
avoidance of this area after pile driving stops is unknown, but a rapid 
return to normal recruitment, distribution and behavior is anticipated. 
In general, impacts to marine mammal prey species from the proposed 
project are expected to be minor and temporary due to the relatively 
short timeframe of pile driving and extraction.
    Effects to Foraging Habitat--Pile installation may temporarily 
impact foraging habitat by increasing turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. The Navy must comply with state water quality standards during 
these operations by limiting the extent of turbidity to the immediate 
project area. In general, turbidity associated with pile installation 
is localized to about a 25-foot radius around the pile (Everitt et al. 
1980). Cetaceans are not expected to be close enough to the project 
pile driving areas to experience effects of turbidity, and any 
pinnipeds will be transiting the area and could avoid localized areas 
of turbidity. Therefore, the impact from increased turbidity levels is 
expected to be discountable to marine mammals.
    Impacts to salmonid and forage fish populations, including ESA-
listed species, will be minimized by adhering to the designated in-
water work period. These work periods are designated when out-migrating 
juvenile salmonids are least likely to occur. Some habitat degradation 
is expected during construction, but the impacts to fish species and 
their habitats will be temporary and localized. The presence, shading 
potential, and associated artificial lighting of the larger Service 
Pier structure, because it would exist in offshore waters of at least 
30 feet below MLLW, is not anticipated to alter the behavior of 
juvenile salmonids using the nearshore migratory pathway. Adult 
salmonids would not experience a substantial barrier effect, and there 
would be little or no overall delay in their movements. The numbers of 
marine mammals affected by impacts to prey populations will be small; 
therefore, the impact will be insignificant in the context of marine 
mammal populations.
    It is important to note that pile driving and removal activities at 
the project site will not obstruct movements or migration of marine 
mammals.
    In summary, given the relatively short and intermittent nature of 
sound associated with individual pile driving and extraction events and 
the relatively small area that would be 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. Thus, any impacts to marine mammal habitat are not expected to 
cause significant or long-term consequences for individual marine 
mammals or 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 whether the number of takes is ``small'' and the 
negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as 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 the harbor seal, 
due to larger predicted auditory injury zones and regular presence 
around the waterfront area. Auditory injury is unlikely to occur for 
mid-frequency cetaceans or otariid species due to small predicted 
zones. The proposed mitigation and monitoring measures are expected to 
minimize the severity of such taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the take is estimated.
    Described in the most basic way, we estimate take by considering: 
(1) Acoustic thresholds above which NMFS believes the best available 
science indicates marine mammals will be behaviorally harassed or incur 
some degree of permanent hearing impairment; (2) the area or volume of 
water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and, (4) and the number of days of activities. Below, we describe these 
components in more detail and present the proposed take estimate.

Acoustic Thresholds

    NMFS uses acoustic thresholds that identify the received level of 
underwater sound above which exposed marine mammals would be reasonably 
expected to be behaviorally harassed (equated to Level B harassment) or 
to incur PTS of some degree (equated to Level A harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source (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., 2011). 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 affected in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (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).
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Technical 
Guidance, 2016) 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 Navy's 
proposed activity includes the use of impulsive (impact pile

[[Page 10702]]

driving) and non-impulsive (vibratory pile driving and extraction) 
sources.
    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and peer reviewers to inform the final product, and are 
provided in Table 3. The references, analysis, and methodology used in 
the development of the thresholds are described in NMFS 2016 Technical 
Guidance, which may be accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
[GRAPHIC] [TIFF OMITTED] TN12MR18.003

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    Pile driving will generate underwater noise that potentially could 
result in disturbance to marine mammals swimming by the project area. 
Transmission loss (TL) underwater is the decrease in acoustic intensity 
as an acoustic pressure wave propagates out from a source until the 
source becomes indistinguishable from ambient sound. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. A standard sound propagation model, the Practical 
Spreading Loss model, was used to estimate the range from pile driving 
activity to various expected SPLs at potential project structures. This 
model follows a geometric propagation loss based on the distance from 
the driven pile, resulting in a 4.5 dB reduction in level for each 
doubling of distance from the source. In this model, the SPL at some 
distance away from the source (e.g., driven pile) is governed by a 
measured source level, minus the TL of the energy as it dissipates with 
distance. The TL equation is:

TL = 15log10(R1/R2)

Where:

TL is the transmission loss in dB,
R1 is the distance of the modeled SPL from the driven 
pile, and
R2 is the distance from the driven pile of the initial 
measurement.

    The degree to which underwater noise propagates away from a noise 
source is dependent on a variety of factors, most notably by the water 
bathymetry and presence or absence of reflective or absorptive 
conditions including the sea surface and sediment type. The TL model 
described above was used to calculate the expected noise propagation 
from both impact and vibratory pile driving, using representative 
source levels to estimate

[[Page 10703]]

the zone of influence (ZOI) or area exceeding the noise criteria.

Source Levels

    For the analyses that follow, the TL model described above was used 
to calculate the expected noise propagation from pile driving, using an 
appropriate representative source level from Table 4 to estimate the 
area exceeding the noise criteria. The source levels were derived from 
the Navy's document titled Proxy source sound levels and potential 
bubble curtain attenuation for acoustic modeling of nearshore marine 
pile driving at Navy installations in Puget Sound (Navy 2015). In that 
document the Navy reviewed relevant data available for various types 
and sizes of piles typically used for pile driving and recommend proxy 
source values for Navy installations in Puget Sound. This document may 
be found as Appendix B in the Navy's application. Acoustic monitoring 
was conducted during previous pile driving projects at this location. 
Results were used to establish proxy sound source levels for 36-in 
steel piles.

              Table 4--Underwater Noise Source Levels Modeled for Impact and Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
                                 Installation                      RMS (dB re 1    Peak (dB re 1   SEL (dB re 1
          Pile type                 method        Pile diameter       [mu]Pa)         [mu]Pa)     [mu]Pa\2\ sec)
----------------------------------------------------------------------------------------------------------------
Timber.......................  Vibratory.......  15-18 in (38-45          \1\155             N/A             N/A
                                                  cm).
Concrete.....................  Impact..........  18 in (45 cm)..             170             184             159
Steel........................  Impact..........  24 in (60 cm)..             193             210             181
                                                 36 (90 cm).....             194             211             181
                               Vibratory.......  24 (60 cm).....             161             N/A             N/A
                                                 36 (90 cm).....             166             N/A             N/A
----------------------------------------------------------------------------------------------------------------
\1\ Navy opted to use conservative value of 155 dB for project.
Key: cm = centimeter; dB re 1 [mu]Pa = decibels referenced at 1 micropascal; N/A = not applicable; RMS = root
  mean square; SEL = sound exposure level.

    For vibratory pile driving distances to the PTS thresholds, the TL 
model described above incorporated the auditory weighting functions for 
each hearing group using a single frequency as described in the NMFS 
Optional Spreadsheet (NMFS, 2016b). When 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 Level A 
take. However, these tools offer the best way to predict appropriate 
isopleths when more sophisticated 3D modeling methods are not 
available. NMFS continues to develop ways to quantitatively refine 
these tools, and will qualitatively address the output where 
appropriate. For stationary sources, including pile driving, NMFS User 
Spreadsheet predicts the closest distance at which a marine mammal, if 
it remained beyond that distance the whole duration of the activity, 
would not incur PTS.
    For impact pile driving distances to the cumulative PTS thresholds 
for 36-inch (90 cm) and 24-inch (60 cm) steel and concrete pile, the TL 
model described above incorporated frequency weighting adjustments by 
applying the auditory weighting function over the entire 1-second SEL 
spectral data sets from impact pile driving. The Navy believes, and 
NMFS concurs, that this methodology provides a closer estimate than 
applying the weighting function at a single frequency as suggested in 
the NMFS Spreadsheet. The NMFS Spreadsheet is considered to be a 
conservative method that typically results in higher estimates of the 
PTS onset distance from the pile driving activity. The Navy analysis 
focused on the data provided from the Naval Kitsap Bangor Test Pile 
Program (steel piles) and the Puget Sound Naval Shipyard Intermediate 
Maintenance Facility Pier 6 Fender Pile Replacement Project (concrete 
piles) (Grebner et al., 2016). This analysis is described in more 
detail in Appendix C.
    An unconfined bubble curtain will be used during impact driving of 
steel piles, since the project is located in an area without high 
currents. While bubble curtain performance is variable, data from the 
Bangor Naval Base Test Pile Program indicated an average peak SPL 
reduction of 8 dB to 10 dB at 10 meters was achieved for impact driving 
of 36- and 48-inch steel pipes (Navy 2015). However, for the SPE 
project, a reduction of 8 dB was utilized as shown in Table 5.

                                         Table 5--Inputs for Determining Distances to Cumulative PTS Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             18'' Concrete        24'' Steel          36'' Steel
                                  36'' Steel  impact  24'' Steel  impact        impact             vibratory           vibratory            Timber
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         INPUTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............  (E.1-2) Impact      (E.1-2) Impact      (E.1-2) Impact      (A.1) Vibratory     (A.1) Vibratory     (A.1) Vibratory
                                   pile driving.       pile driving.       pile driving.       pile driving.       pile driving.       pile driving.
Source Level (Single Strike/shot  173 dB (assumes 8   173 dB (assumes 8   159 dB............
 SEL).                             dB attenuation) *.  dB attenuation) *.
Source Level (RMS SPL)..........  ..................  ..................  ..................  161 dB............  166 dB............  155.
Weighting Factor Adjustment       Weighting override  Weighting override  Weighting override  2.5...............  2.5...............  2.5.
 (kHz) **.                         (Grebner et al.     (Grebner et al.     (Grebner et al.
                                   2016).              2016).              2016).
Number of strikes per day.......  1,600.............  1,600.............  1,600.............
Number of piles per day within    2.................  1.................  3.................
 24-h period.
Duration of sound Production      ..................  ..................  ..................  300...............  300...............  300.
 (minutes).
Propagation (xLogR).............  15................  15................  15................  15................  15................  15.

[[Page 10704]]

 
Distance of source level          10................  10................  10................  10................  10................  10.
 measurement (meters).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* 8 dB reduction from use of unconfined bubble curtain during steel pipe impact driving.
** For impact driving, the TL model described above incorporated frequency weighting adjustments by applying the auditory weighting function over the
  entire 1-second SEL spectral data sets.


Table 6--Calculated Radial Distances (Meters) to Underwater Marine Mammal Impact Pile Driving Noise Thresholds--
                                              SELCUM Isopleths \1\
----------------------------------------------------------------------------------------------------------------
                                                               Level A isopleths--impact driving \2\
                                                 ---------------------------------------------------------------
                   Source type                                         High-
                                                   Mid-frequency     frequency        Phocid          Otariid
                                                     cetaceans       cetaceans       pinnipeds       pinnipeds
----------------------------------------------------------------------------------------------------------------
18-in concrete \3\..............................               2              74              19               1
24-in steel \4\.................................               5             253              34               2
36-in steel \4\.................................              14             740             217              12
----------------------------------------------------------------------------------------------------------------
Notes:
1. Calculations based on SELCUM threshold criteria shown in Table 3.
Calculated values were rounded up the nearest meter.
2. Representative spectra were used to calculate the distances to the injury (PTS onset) thresholds for each
  functional hearing group for 24-inch and 36-inch steel pile and 24-inch (60 cm) concrete pile. Distances for
  18-inch (45 cm) concrete piles assumed to be the same as 24-inch (60 cm) concrete piles.
3. No bubble curtain proposed for concrete pile.
4. Bubble curtain will be used for 24-inch (60 cm) and 36-inch (90 cm) steel piles, and calculations include 8
  dB attenuation.


 Table 7--Calculated Radial Distances (Meters) to Level A Underwater Marine Mammal Vibratory Pile Driving Noise
                                                    Isopleths
----------------------------------------------------------------------------------------------------------------
                                                     Level A isopleths--Vibratory driving \1\
                                 -------------------------------------------------------------------------------
           Source type                                                 High-
                                   Low-frequency   Mid-frequency     frequency        Phocid          Otariid
                                     cetaceans       cetaceans       cetaceans       pinnipeds       pinnipeds
----------------------------------------------------------------------------------------------------------------
15-18-in timber.................               8              <1              12               5              <1
24-in steel.....................              20               2              30              12               1
36-in steel.....................              43               4              64              26             1.8
----------------------------------------------------------------------------------------------------------------
Notes:
1. Distances to the injury (PTS onset) thresholds calculated using National Marine Fisheries Service calculator
  with default Weighting Factor Adjustment of 2.5 (NMFS, 2016b).
Calculated values were rounded up the nearest meter.

    Tables 6 and 7 show the radial distances to impact and vibratory 
Level A isopleths. Based on the dual criteria provided in the NMFS 
Spreadsheet, the cumulative SEL was selected over peak threshold to 
calculate injury thresholds because the ensonified distances were 
larger.
    Using the same source level and transmission loss inputs discussed 
above the Level B isopleths were calculated for impact and vibratory 
driving (Table 8). Note that these attenuation distances are based on 
sound characteristics in open water. The actual attenuation distances 
are constrained by numerous land features and islands; these actual 
distances are reflected in the ensonified areas given below.

           Table 8--Level B Impact and Vibratory Pile Driving Exposure Distances and Ensonified Areas
----------------------------------------------------------------------------------------------------------------
                     Pile type                          Attenuation  distance                  Area *
----------------------------------------------------------------------------------------------------------------
                                                 Impact (160 dB)
----------------------------------------------------------------------------------------------------------------
18-in concrete....................................  46 m.........................  6.64 m\2\.
24-in steel.......................................  464 m........................  0.62 km\2\.
36-in steel.......................................  541 m........................  0.78 km\2\.
----------------------------------------------------------------------------------------------------------------
                                               Vibratory (120 dB)
----------------------------------------------------------------------------------------------------------------
15-18-in timber...................................  2.2 km.......................  6.8 km\2\.
24-in steel.......................................  5.4 km.......................  26.1 km\2\.
36-in steel.......................................  11.7 km......................  49.6 km\2\.
----------------------------------------------------------------------------------------------------------------
* Areas were adjusted wherever land masses are encountered prior to reaching the full extent of the radius
  around the driven pile.


[[Page 10705]]

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    Transient killer whales are rare in Hood Canal and there are few 
data to describe transient killer whale abundance within Hood Canal. 
There have been anecdotal accounts of the whales in Hood Canal for 
decades. There was a report from 1 day in April 2016 and 8 days in May 
2016 of whales Dabob Bay (Orca Network, 2016). It is likely that the 
whales were using Hood Canal as part of a larger area moving in and out 
of Hood Canal. It is not known how large an area these animals were 
using; it is also unknown if these sightings were all of the same group 
of transient killer whales, or if animals were using the same areas. 
However, the temporally discontinuous data suggest a high degree of 
variability in the habitat use and localized relative abundances of 
transient killer whales in Hood Canal. Given that whales were observed 
on eight days, in May 2016, NMFS will assume that whales could be 
observed on up to 8 days during the SPE project. The most commonly 
observed group size in Puget Sound from 2004 to 2010 was 6 whales (Navy 
2017).
    Harbor porpoises may be present in Puget Sound year-round typically 
in groups of one to five individuals and are regularly detected in Hood 
Canal. Aerial surveys conducted throughout 2013 to 2015 in Puget Sound 
indicated density in Puget Sound was 0.91 individuals/km\2\) (95% CI = 
0.72-1.10, all seasons pooled) and density in Hood Canal was 0.47/km\2\ 
(95% CI = 0.29-0.75, all seasons pooled) (Jefferson et al., 2016). 
However, after reviewing the most recent data the Navy has estimated 
that harbor porpoise density in Hood Canal is 0.44 animals/km\2\ 
(Smultea et al., 2017). Mean group size of harbor porpoises in Puget 
Sound in the 2013-2015 surveys was 1.7 in Hood Canal.
    Steller sea lions are routinely seen hauled out on submarines at 
Naval Base Kitsap. The Navy relied on monitoring data from 2012 to 2016 
to determine the average of the maximum count of hauled out Steller sea 
lions for each month in the in-water work window (Appendix A). The 
average of the monthly maximum counts during the in-water work window 
was 3.14, rounded to 3 exposures per day.
    California sea lions can occur at Naval Base Kitsap Bangor in any 
month, although numbers are low from June through August (Appendix A in 
the application).
    California sea lions peak abundance occurs between October and May 
(NMFS, 1997; Jeffries et al., 2000) but animals can occur at Naval Base 
Kitsap Bangor in any month. The Navy relied on monitoring data from 
2012 to 2016 to determine the average of the maximum count of hauled 
out California sea lions for each month (Appendix A). The Navy 
determined abundance of California sea lions based on the average 
monthly maximum counts during the in-water work window (Appendix A), 
respectively, for an average maximum count of 48.85, rounded to 49 
exposures per day.
    Boat-based surveys and monitoring indicate that harbor seals 
regularly swim in the waters at Naval Base Kitsap Bangor (Appendix A in 
Application). Hauled-out adults, mother/pup pairs, and neonates have 
been documented occasionally, but quantitative data are limited. 
Incidental surveys in August and September 2016 recorded as many as 28 
harbor seals hauled out under Marginal Wharf or swimming in adjacent 
waters. Additional animals were likely present at other locations 
during the same time of the surveys. To be conservative, the Navy 
estimated that an additional 7 animals were present based on typical 
sightings at the other piers at Bangor. Therefore, the Navy and NMFS 
assume that up to 35 seals could occur near the SPE project area on any 
given day.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    To quantitatively assess exposure of marine mammals to noise levels 
from pile driving over the NMFS threshold guidance, one of three 
methods was used depending on the species spatial and temporal 
occurrence. For species with rare or infrequent occurrence during the 
in-water work window, the likelihood of occurrence was reviewed based 
on the information in Chapter 3 of the application and the potential 
maximum duration of work days and total work days. Only one species was 
in this category, transient killer whale, and it had the potential to 
linger for multiple days based on historical information. The 
calculation was:

(1) Exposure estimate = Probable abundance during construction x 
Probable duration

Where:

Probable abundance = maximum expected group size
Probable duration = probable duration of animal(s) presence at 
construction sites during in-water work window

    For species that regularly occur in Puget Sound, but for which 
local abundance data are not available, marine mammal density estimates 
were used when available to determine the number of animals potentially 
exposed in a ZOI on any one day of pile driving or extraction. Only 
harbor porpoise was in this category.
    The equation for this species with only a density estimate and no 
site-specific abundance was:

(2) Exposure estimate = N x ZOI x maximum days of pile driving

Where:

N = density estimate used for each species
ZOI = Zone of Influence; the area where noise exceeds the noise 
threshold value

    For species with site-specific surveys available, exposures were 
estimated by:

    (3) Exposure estimate = Abundance x maximum days of pile driving

Where:

Abundance = average monthly maximum over the time period when pile 
driving will occur for sea lions, and estimated total abundance for 
harbor seals

    All three pinniped species were in this category. Average monthly 
maximum counts of Steller sea lions and California sea lions (see 
Appendix A for abundance data of these species) were averaged over the 
in-water work window. The maximum number of animals observed during the 
month(s) with the highest number of animals present on a survey day was 
used in the analysis. For harbor seals, an abundance estimate for the 
Bangor waterfront was used.
    The following assumptions were used to calculate potential 
exposures to impact and vibratory pile driving noise for each 
threshold.
     For formulas (2) and (3), each species will be assumed to 
be present in the project area each day during construction. The 
timeframe for takings would be one potential take (Level B harassment 
exposure) per individual, per 24 hours.
     The pile type, size, and installation method that produce 
the largest ZOI were used to estimate exposure of marine mammals to 
noise impacts. Vibratory installation of 36-inch (90 cm) steel piles 
created the largest ZOI, so the exposure analysis calculates marine 
mammal exposures based on 36- inch steel piles for the 125 days when 
steel piles would be installed. For the estimated 35 days when concrete 
fender piles would be installed, impact driving was the only 
installation method and only 18-inch piles were proposed, so the 
exposure analysis calculated marine mammal exposures based on impact 
driving 18-inch concrete piles.

[[Page 10706]]

     All pilings will have an underwater noise disturbance 
distance equal to the pile that causes the greatest noise disturbance 
(i.e., the piling farthest from shore) installed with the method that 
has the largest ZOI. If vibratory pile driving would occur, the largest 
ZOI will be produced by vibratory driving. In this case, the ZOI for an 
impact hammer will be encompassed by the larger ZOI from the vibratory 
driver. Vibratory driving was assumed to occur on all 125 days of steel 
pile driving, but not the 35 days of concrete fender pile installation.
     Days of pile driving were conservatively based on a 
relatively slow daily production rate, but actual daily production 
rates may be higher, resulting in fewer actual pile driving days. The 
pile driving days are used solely to assess the number of days during 
which pile driving could occur if production was delayed due to 
equipment failure, safety, etc. In a real construction situation, pile 
driving production rates would be maximized when possible.

Transient Killer Whale

    Using the first calculation described in the above section, 
exposures to underwater pile driving were calculated using the average 
group size times the 8 days transient killer whales would be 
anticipated in the Hood Canal during pile driving activities. The Navy 
assumed that the average pod size was six individuals.
    Using this rationale, 48 potential Level B exposures of transient 
killer whales from vibratory pile driving are estimated (six animals 
times 8 days of exposure). Based on this analysis, the Navy requests 
and NMFS proposes 48 Level B incidental takes for behavioral 
harassment. Concrete and steel ZOIs from impact driving will be fully 
monitorable (maximum distances to behavioral thresholds of 46 m and 541 
m, respectively, and maximum distance to injury thresholds is 14 m), so 
no killer whale behavioral or injury takes are expected from impact 
driving.

Harbor Porpoise

    Applying formula (2) to the animal density (0.44animals/km \2\), 
the largest ZOI for Level B exposure (49.6 km \2\) and the estimated 
days of steel pile driving (125), the Navy requests and NMFS proposes 
2,728 Level B incidental takes of harbor porpoises. The 49.6 km \2\ ZOI 
excludes the area behind the PSB because harbor porpoise have never 
been observed within the barrier. Harbor porpoise can be visually 
detected to a distance of about 200 m by experienced observers in 
conditions up to Beaufort 2 (Navy 2017). Therefore, the concrete ZOIs 
will be fully monitorable (maximum distance of 46 m), so no takes were 
calculated for the estimated 35 days of concrete fender pile 
installation.

Steller Sea Lion

    Concrete ZOIs will be fully monitorable, so no takes were 
calculated for the estimated 35 days of concrete fender pile 
installation. Formula (3) as described in the previous section was used 
with site-specific abundance data to calculate potential exposures of 
Steller sea lions during steel pile driving for the SPE project. 
Animals could be exposed when traveling, resting, and foraging. Because 
a Level A injury shut-down zone will be implemented, Level A harassment 
is not expected to occur.
    The Navy conservatively assumes that any Steller sea lion that 
hauls out at Bangor could swim into the behavioral harassment zone each 
day during pile driving because this zone extends across Hood Canal and 
up to 11.7 km from the driven pile. The Navy estimated 3 animals could 
be exposed to harassment per day. These values provide a worst case 
assumption that on all 125 days of pile driving, all animals would be 
in the water each day during pile driving. Applying formula (3) to this 
abundance and the 125 steel pile driving days, the Navy requests and 
NMFS proposes the take of up to 375 Steller sea lions. If project work 
occurs during months when Steller sea lions are less likely to be 
present, actual exposures would be less. Additionally, if daily pile 
driving duration is short, exposure would be expected to be less 
because some animals would remain hauled out for the duration of pile 
driving. Any exposure of Steller sea lions to pile driving noise will 
be minimized to short-term behavioral harassment.

California Sea Lion

    Concrete ZOIs will be fully monitorable (maximum distance of 46 m), 
so no takes were calculated for the estimated 35 days of concrete 
fender pile installation (Figure 6-3 in application). Formula (3) was 
used with site-specific abundance data to calculate potential exposures 
of California sea lions during pile driving for the SPE project. 
Because a Level A injury shut-down zone will be implemented, no 
exposure to Level A noise levels will occur at any location. Based on 
site-specific data regarding the average maximum counts, the Navy 
assumes that 49 exposures per day could occur over 125 planned steel 
pile driving days. Therefore, NMFS proposes authorizing 6,125 Level B 
takes.

Harbor Seal

    The Navy calculated up to 35 harbor seals may be present per day 
during summer and early fall months. Exposure of harbor seals to pile 
driving noise will be primarily in the form of short-term behavioral 
harassment (Level B) during steel pile driving. Concrete ZOIs will be 
fully monitorable (maximum distance of 46 m), so no takes were 
calculated for the estimated 35 days of concrete fender pile 
installation (Figure 6-3 in application). Formula (3) was used with 
site-specific abundance data to calculate potential exposures of harbor 
seals due to pile driving for the SPE.
    The Navy assumes that any harbor seal that hauls out at Bangor 
could swim into the behavioral harassment zone each day during impact 
pile driving. The largest ZOI for behavioral disturbance (Level B) 
would be 11.7 km for vibratory driving and extraction of 36-inch steel 
piles. Applying formula (3) to the abundance of this species (35 
individuals) and the 125 pile driving days, the Navy requests and NMFS 
proposes the Level A and Level B take of up to 4,375 harbor seals 
during pile driving for the SPE. The largest ZOI for Level A injury 
will be 217 m for impact driving (with bubble curtain) of 36-inch steel 
piles. A monitors' ability to observe the entire 217 m injury zone may 
be difficult because construction barges and the current Service Pier 
structure and associated mooring floats and vessels will interfere with 
a monitors' ability to observe the entire injury zone. Some individuals 
could enter, and remain in, the injury zone undetected by monitors, 
resulting in potential PTS. It is estimated that one of the 35 
individuals present on the Bangor waterfront would enter, and remain 
in, the injury zone without being detected by marine mammal monitors 
each day during steel impact driving. Therefore, with 125 steel pile 
driving days and one individual per day being exposed to Level A noise 
levels, 125 Level A takes of harbor seals are proposed by NMFS. 
Subtracting 125 Level A takes from the estimated total of 4,375 takes 
would result in 4,250 Level B takes. It should be noted that Level A 
takes of harbor seals would likely be multiple exposures of the same 
individuals, rather than single exposures of unique individuals. This 
request overestimates the likely Level A exposures because: (1) Seals 
are unlikely to remain in the Level A zone underwater long enough to 
accumulate sufficient exposure to noise resulting in PTS, and (2) the 
estimate assumes that new seals are in the Level A ZOI every day during 
pile driving. No Level A

[[Page 10707]]

takes are requested for vibratory pile driving because the maximum 
harbor seal injury zone is 15 m and is within a practicable shutdown 
distance. It is important to note that the estimate of potential Level 
A harassment of harbor seals is expected to be an overestimate, since 
the planned project is not expected to occur near Marginal Wharf--the 
location where most harbor seal activity occurs.
    Table 9 provides a summary of proposed authorized Level A and Level 
B takes as well as the percentage of a stock or population proposed for 
take.

                     Table 9--Proposed Authorized Take and Percentage of Stock or Population
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed authorized take
                             Species                             --------------------------------     Percent
                                                                      Level A         Level B       population
----------------------------------------------------------------------------------------------------------------
Killer whale....................................................               0              48            19.7
Harbor porpoise.................................................               0           2,728            24.3
Steller sea lion................................................               0             375             0.9
California sea lion.............................................               0           6,125             2.0
Harbor seal.....................................................             125           4,250             n/a
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such 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 such 
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.
    In addition to the specific measures described later in this 
section, the Navy would conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, and Navy staff 
prior to the start of all pile driving activity, and when new personnel 
join the work, in order to explain responsibilities, communication 
procedures, marine mammal monitoring protocol, and operational 
procedures.
    Use of Vibratory Installation--The Navy will employ vibratory 
installation to the greatest extent possible when driving steel piles 
to minimize high sound pressure levels associated with impact pile 
driving. Impact driving of steel piles will only occur when required by 
geotechnical conditions or to ``proof'' load-bearing piles driven by 
vibratory methods.
    Timing Restrictions--To minimize the number of fish exposed to 
underwater noise and other construction disturbance, in-water work will 
occur during the in-water work window previously described when ESA-
listed salmonids are least likely to be present (USACE, 2015), July 16-
January 15.
    All in-water construction activities will occur during daylight 
hours (sunrise to sunset) except from July 16 to September 15, when 
impact pile driving will only occur starting 2 hours after sunrise and 
ending 2 hours before sunset, to protect foraging marbled murrelets 
during the nesting season (April 15-September 23). Sunrise and sunset 
are to be determined based on National Oceanic and Atmospheric 
Administration data, which can be found at https://www.srrb.noaa.gov/highlights/sunrise/sunrise.html.
    Use of Bubble Curtain--A bubble curtain or other noise attenuation 
device that achieves an average of at least 8 dB of noise attenuation 
will be employed during impact installation or proofing of steel piles 
where water depths are greater than 0.67 m (2 ft). A noise attenuation 
device is not required during vibratory pile driving. If a bubble 
curtain or similar measure is used, it will distribute air bubbles 
around 100 percent of the piling perimeter for the full depth of the 
water column. Any other attenuation measure must provide 100 percent 
coverage in the water column for the full depth of the pile. The lowest 
bubble ring shall be in contact with the mudline for the full 
circumference of the ring. The weights attached to the bottom ring 
shall ensure 100 percent mudline contact. No parts of the ring or other 
objects shall prevent full mudline contact.
    A performance test of the noise attenuation device shall be 
conducted prior to initial use for impact pile driving. If a bubble 
curtain or similar measure is utilized, the performance test shall 
confirm the calculated pressures and flow rates at each manifold ring. 
The contractor shall also train personnel in the proper balancing of 
air flow to the bubblers. The contractor shall submit an inspection/
performance report to the Navy for approval within 72 hours following 
the performance test. Corrections to the noise attenuation device to 
meet the performance stands shall occur prior to use for impact 
driving.
    If the U.S. Fish and Wildlife Service concurs that turning off the 
noise attenuation will not negatively impact marbled murrelets, 
baseline sound measurements of steel pile driving will occur prior to 
the implementation of noise attenuation to evaluate the performance of 
a noise attenuation device. Impact pile driving without

[[Page 10708]]

noise attenuation will be limited to the number of piles necessary to 
obtain an adequate sample size for each project.
    Soft-Start--The use of a soft start procedure is believed to 
provide additional protection to marine mammals by warning or providing 
a chance to leave the area prior to the hammer operating at full 
capacity, and typically involves a requirement to initiate sound from 
the hammer at reduced energy followed by a waiting period. A soft-start 
procedure will be used for impact pile driving at the beginning of each 
day's in-water pile driving or any time impact pile driving has ceased 
for more than 30 minutes.
    The Navy will start the bubble curtain prior to the initiation of 
impact pile driving. The contractor will provide an initial set of 
strikes from the impact hammer at reduced energy, followed by a 30-
second waiting period, then two subsequent sets. (The reduced energy of 
an individual hammer cannot be quantified because it varies by 
individual drivers. Also, the number of strikes will vary at reduced 
energy because raising the hammer at less than full power and then 
releasing it results in the hammer ``bouncing'' as it strikes the pile, 
resulting in multiple ``strikes.'')
    Establishment of Shutdown Zones and Disturbance Zones--For all 
impact and vibratory pile driving of steel piles, shutdown and 
disturbance zones will be established and monitored. The Navy will 
focus observations within 1,000 m for all species during these 
activities but will record all observations. During impact driving of 
concrete piles the Navy will focus on monitoring within 100 m but will 
record all observations. The Navy will monitor and record marine mammal 
observations within zones and extrapolate these values across the 
entirety of the Level B zone as part of the final monitoring report. To 
the extent possible, the Navy will record and report on any marine 
mammal occurrences, including behavioral disturbances, beyond 1,000 m 
for steel pile installation and 100 m for concrete pile installation.
    The shutdown zones are based on the distances from the source 
predicted for each threshold level. Although different functional 
hearing groups of cetaceans and pinnipeds were evaluated, the threshold 
levels used to develop the disturbance zones were selected to be 
conservative for cetaceans (and therefore at the lowest levels); as 
such, the disturbance zones for cetaceans were based on the high 
frequency threshold (harbor porpoise). The shutdown zones are based on 
the maximum calculated Level A radius for pinnipeds and cetaceans 
during installation of 36-inch steel and concrete piles with impact 
techniques, as well as during vibratory pile installation and removal. 
These actions serve to protect marine mammals, allow for practical 
implementation of the Navy's marine mammal monitoring plan and reduce 
the risk of a take. The shutdown zone during any non-pile driving 
activity will always be a minimum of 10 m (33 ft) to prevent injury 
from physical interaction of marine mammals with construction 
equipment.
    During all pile driving, the shutdown, Level A, and Level B zones 
as shown in Tables 10, 11, and 12 will be monitored out to the greatest 
extent possible with a focus on monitoring within 1,000 m for steel 
pile and 100 m for concrete pile installation.
    For steel pile impact pile driving, monitors would initiate 
shutdown when harbor seals approach or enter the zone. However, because 
of the size of the zone and the inherent difficulty in monitoring 
harbor seals, a highly mobile species, it may not be practical, which 
is why Level A take is requested.
    The isopleths delineating shutdown, Level A, and Level B zones 
during impact driving of all steel piles are shown in Table 10. Note 
that the Level A isopleth is larger than the Level B isopleth for 
harbor porpoises.

             Table 10--Shutdown, Level A, and Level B Isopleths During Impact Driving of Steel Piles
----------------------------------------------------------------------------------------------------------------
                                                                      Level B         Level A
                       Marine mammal group                           isopleth        isopleth      Shutdown zone
                                                                     (meters)        (meters)        (meters)
----------------------------------------------------------------------------------------------------------------
Cetaceans (Harbor Porpoise).....................................             541             740           1,000
Harbor Seal.....................................................             541             217             220
Sea Lions.......................................................             541              12             220
----------------------------------------------------------------------------------------------------------------

    The isopleths for the shutdown, Level A, and Level B zones during 
vibratory driving of all steel piles are shown in Table 11.

             Table 11--Shutdown, Level A, Level B Isopleths During Vibratory Driving of Steel Piles
----------------------------------------------------------------------------------------------------------------
                                                                      Level B         Level A
                       Marine mammal group                           isopleth        isopleth     Shutdown  zone
                                                                     (meters)        (meters)        (meters)
----------------------------------------------------------------------------------------------------------------
Cetaceans (Harbor Porpoise).....................................          11,700              64             100
Harbor Seal.....................................................          11,700              26              30
Sea Lions.......................................................          11,700             1.8              30
----------------------------------------------------------------------------------------------------------------

    The shutdown, Level A, and Level B isopleths for implementation 
during impact driving of concrete piles are shown in Table 12. Given 
that the shutdown zone for all authorized species is larger than the 
Level A and Level B isopleths there should be no take recorded during 
concrete pile driving.

[[Page 10709]]



           Table 12--Shutdown, Level A, and Level B Isopleths During Impact Driving of Concrete Piles
----------------------------------------------------------------------------------------------------------------
                                                                      Level B         Level A
                       Marine mammal group                           isopleth        isopleth     Shutdown  zone
                                                                     (meters)        (meters)        (meters)
----------------------------------------------------------------------------------------------------------------
Cetaceans (Harbor Porpoise).....................................              46              74             100
Harbor Seal.....................................................              46              19              50
Sea Lions.......................................................              46               1              50
----------------------------------------------------------------------------------------------------------------

    Note that the radii of the disturbance zones may be adjusted if in-
situ acoustic monitoring is conducted by the Navy to establish actual 
distances to the thresholds for a specific pile type and installation 
method. However, any proposed acoustical monitoring plan must be pre-
approved by NMFS. The results of any acoustic monitoring plan must be 
reviewed and approved by NMFS before the radii of any disturbance zones 
may be revised.
    The mitigation measures described above should reduce marine 
mammals' potential exposure to underwater noise levels which could 
result in injury or behavioral harassment. 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: Action or environment (e.g., 
source characterization, propagation, ambient noise); (2) affected 
species (e.g., life history, dive patterns); (3) co-occurrence of 
marine mammal species with the action; or (4) biological or behavioral 
context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring will include the following proposed 
requirements.
    Marine Mammal Observers (MMOs) will be positioned at the best 
practicable vantage points, taking into consideration security, safety, 
and space limitations. During pile driving, one MMO will be stationed 
in a vessel, and at least four will be stationed on the pier, along the 
shore, or on the pile driving barge to maximize observation coverage. 
Each MMO location will have a minimum of one dedicated MMO (not 
including boat operators). The exact number of MMOs and the observation 
locations are to be determined based upon site accessibility and line 
of sight for adequate coverage. It is expected that a minimum of four 
MMOs will be required, with additional MMOs added into the protocol as 
deemed necessary for effective coverage. Additional standards required 
for visual monitoring include:
    (a) Independent observers (i.e., not construction personal) are 
required;
    (b) At least one observer must have prior experience working as an 
observer;
    (c) Other observers may substitute education (undergraduate degree 
in biological science or related field) or training for experience;
    (d) Where a team of three or more observers are required, one 
observer should be designated as lead observer or monitoring 
coordinator. The lead observer must have prior experience working as an 
observer; and
    (e) We will require submission and approval of observer CVs.
    Monitoring will be conducted by qualified observers, who will 
monitor for marine mammals and implement shutdown/delay procedures when 
applicable by calling for the shutdown to the hammer operator. 
Qualified observers are trained biologists, with the following minimum 
qualifications:
    (a) Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
    (b) Advanced education in biological science or related field 
(undergraduate degree or higher required);
    (c) Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
    (d) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (e) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (f) 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 and times when in-water construction activities were 
suspended to avoid potential incidental injury from construction sound 
of marine mammals observed within a defined shutdown zone; and marine 
mammal behavior; and

[[Page 10710]]

    (g) 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.
    MMOs will survey the disturbance zone 15 minutes prior to 
initiation of pile driving through 30 minutes after completion of pile 
driving to ensure there are no marine mammals present. In case of 
reduced visibility due to weather or sea state, the MMOs must be able 
to see the shutdown zones or pile driving will not be initiated until 
visibility in these zones improves to acceptable levels. Marine Mammal 
Observation Record forms (Appendix A of the application) will be used 
to document observations. Survey boats engaged in marine mammal 
monitoring will maintain speeds equal to or less than 10 knots.
    MMOs will use binoculars and the naked eye to search continuously 
for marine mammals and will have a means to communicate with each other 
to discuss relevant marine mammal information (e.g., animal sighted but 
submerged with direction of last sighting). MMOs will have the ability 
to correctly measure or estimate the animals distance to the pile 
driving equipment such that records of any takes are accurate relevant 
to the pile size and type.
    Shutdown shall occur if a species for which authorization has not 
been granted or for which the authorized numbers of takes have been 
met. The Navy shall then contact NMFS within 24 hours.
    If marine mammal(s) are present within or approaching a shutdown 
zone prior to pile driving, the start of these activities will be 
delayed until the animal(s) have left the zone voluntarily and have 
been visually confirmed beyond the shutdown zone, or 15 minutes has 
elapsed without re-detection of the animal.
    If animal is observed within or entering the Level B zone during 
pile driving, a take would be recorded, behaviors documented. However, 
that pile segment would be completed without cessation, unless the 
animal approaches or enters the shutdown Zone, at which point all pile 
driving activities will be halted. The MMOs shall immediately radio to 
alert the monitoring coordinator/construction contractor. This action 
will require an immediate ``all-stop'' on pile operations. Once a 
shutdown has been initiated, pile driving will be delayed until the 
animal has voluntarily left the Shutdown Zone and has been visually 
confirmed beyond the Shutdown Zone, or 15 minutes have passed without 
re-detection of the animal (i.e., the zone is deemed clear of marine 
mammals).
    All marine mammals observed within the disturbance zones during 
pile driving activities will be recorded by MMOs. These animals will be 
documented as Level A or Level B takes as appropriate. Additionally, 
all shutdowns shall be recorded. For vibratory driving activities, this 
data will be extrapolated across the full extent of the Level B 
ensonified zone (i.e. 11.7 km radii) to provide total estimated take 
numbers.
    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated marine 
mammal observation data sheets. Specifically, the report must include 
information as described in the Marine Mammal Monitoring Report 
(Appendix D of the application).
    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.
    In the unanticipated event that: (1) The specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality; (2) an 
injured or dead animal is discovered and cause of death is known; or 
(3) an injured or dead animal is discovered and cause of death is not 
related to the authorized activities, the Navy will follow the 
protocols described in the Section 3 of Marine Mammal Monitoring Report 
(Appendix D of the application).

Negligible Impact Analysis and Preliminary 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 extraction associated with the Navy SPE project as 
outlined previously have the potential to injure, disturb or displace 
marine mammals. Specifically, the specified activities may result in 
Level B harassment (behavioral disturbance) for five marine mammal 
species authorized for take from underwater sound generated during pile 
driving operations. Level A harassment in the form of PTS may also 
occur to limited numbers of one species. Level A harassment was 
conservatively authorized for harbor seals since seals can occur in 
high numbers near the project area, can be difficult to spot, and MMO's 
ability to observe the entire 217 m injury zone may be slightly 
impaired because of construction barges and vessels. Potential takes 
could occur if marine mammals are present in the Level A or Level B 
ensonified zones when pile driving and removal occurs.
    No serious injury or mortality is anticipated given the nature of 
the activities and measures designed to minimize the possibility of 
injury to marine mammals. The potential for injury is minimized through 
the construction method and the implementation of the planned 
mitigation measures. Specifically, vibratory driving will be the 
primary method of installation. This driving method decreases the 
potential for injury due to relatively low source levels and lack of 
potentially injurious source characteristics. Only piles that cannot be 
driven to their desired depths using the vibratory hammer will be 
impact driven for the remainder of their required driving depth. Noise 
attenuating devices (i.e., bubble curtain) will be used during impact 
hammer operations for steel piles. During impact driving, 
implementation of soft start and shutdown zones significantly reduces 
any possibility of injury. Given

[[Page 10711]]

sufficient ``notice'' through use of soft start (for impact driving), 
marine mammals are expected to move away from a sound source that is 
annoying prior to it becoming potentially injurious. Given the number 
of MMOs that will be employed, observers should have a relatively clear 
view of the shutdown zones, although under limited circumstances the 
presence of barges and vessels may impair observation of small portions 
of shutdown zones. This will enable a high rate of success in 
implementation of shutdowns to avoid injury.
    The Navy's planned activities are highly localized. Only a 
relatively small portion of Hood Canal may be affected. The project is 
not expected to have significant adverse effects on marine mammal 
habitat. No important feeding and/or reproductive areas for marine 
mammals are known to be near the project area. Impacts to salmonid and 
forage fish populations, including ESA-listed species, will be 
minimized by adhering to the designated in-water work period. Project-
related activities may cause some fish to leave the area of 
disturbance, thus temporarily impacting marine mammals' foraging 
opportunities in a limited portion of the foraging range, but because 
of the relatively small area of the habitat range utilized by each 
species that may be affected, the impacts to marine mammal habitat are 
not expected to cause significant or long-term negative consequences.
    Exposures to elevated sound levels produced during pile driving 
activities may cause behavioral responses by an animal, but they are 
expected to be mild and temporary. Effects on individuals that are 
taken by Level B harassment, on the basis of reports in the literature 
as well as monitoring from other similar activities, will likely be 
limited to reactions such as increased swimming speeds, increased 
surfacing time, or decreased foraging (if such activity were occurring) 
(e.g., Thorson and Reyff, 2006; Lerma, 2014). Most likely, individuals 
will simply move away from the sound source and be temporarily 
displaced from the areas of pile driving, although even this reaction 
has been observed primarily only in association with impact pile 
driving. These reactions and behavioral changes are expected to subside 
quickly when the exposures cease. The pile driving activities analyzed 
here are similar to, or less impactful than, numerous construction 
activities conducted in other similar locations including Hood Canal, 
which have taken place with no reported injuries or mortality to marine 
mammals, and no known long-term adverse consequences from behavioral 
harassment. Repeated exposures of individuals to levels of sound that 
may cause Level B harassment are unlikely to result in permanent 
hearing impairment or to significantly disrupt foraging behavior. Level 
B harassment will be reduced through use of mitigation measures 
described herein.
    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 
stocks through effects on annual rates of recruitment or survival:
     No mortality or serious injury is anticipated or 
authorized;
     The area of potential impacts is highly localized;
     No adverse impacts to marine mammal habitat;
     The absence of any significant habitat within the project 
area, including rookeries, or known areas or features of special 
significance for foraging or reproduction;
     Anticipated incidences of Level A harassment would be in 
the form of a small degree of PTS to a limited number of animals;
     Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior;
     The anticipated efficacy of the required mitigation 
measures in reducing the effects of the specified activity.
    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. Additionally, other qualitative factors may 
be considered in the analysis, such as the temporal or spatial scale of 
the activities.
    Table 9 depicts the number of animals that could be exposed to 
Level A and Level B harassment from work associated with the SPE 
project. With the exception of harbor seals, the analysis provided 
indicates that authorized takes account for no more than 24.3 percent 
of the populations of the stocks that could be affected. These are 
small numbers of marine mammals relative to the sizes of the affected 
species and population stocks under consideration.
    For the affected stock of harbor seals, no valid abundance estimate 
is available. The most recent abundance estimates for harbor seals in 
Washington inland waters are from 1999, and it is generally believed 
that harbor seal populations have increased significantly during the 
intervening years (e.g., Mapes, 2013). However, we anticipate that 
takes estimated to occur for harbor seals are likely to occur only 
within some portion of the relevant populations, rather than to animals 
from the stock as a whole. For example, takes anticipated to occur at 
NBK Bangor would be expected to accrue to the same individual seals 
that routinely occur on haulouts at these locations, rather than 
occurring to new seals on each construction day. In summary, harbor 
seals taken as a result of the specified activities are expected to 
comprise only a limited portion of individuals comprising the overall 
relevant stock abundance. Therefore, we preliminarily find that small 
numbers of marine mammals will be taken relative to the population size 
of the Hood Canal stock of harbor seal.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it

[[Page 10712]]

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.
    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 Navy for conducting vibratory and impact pile 
driving associated with the proposed Service Pier Extension (SPE) at 
Naval Base Kitsap Bangor, Washington from October 1, 2018, to September 
30, 2019, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. This section contains a draft 
of the IHA itself. The wording contained in this section is proposed 
for inclusion in the IHA (if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
October 1, 2018 through September 30, 2019. This IHA is valid only for 
pile driving and extraction activities associated with the Naval Base 
Kitsap Bangor SPE project.
    2. General Conditions.
    (a) A copy of this IHA must be in the possession of the Navy, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking are the killer whale (Orcinus 
orca; transient only), harbor porpoise (Phocoena phocoena vomerina), 
California sea lion (Zalophus californianus), Steller sea lion 
(Eumetopias jubatus monteriensis), and harbor seal (Phoca vitulina 
richardii).
    (c) The taking, by Level A and Level B harassment, is limited to 
the species listed in condition 2(b). See Table 11 for numbers of Level 
A and Level B take authorized.
    (d) The take of any other species not listed in condition 2(b) of 
marine mammal is prohibited and may result in the modification, 
suspension, or revocation of this IHA.
    (e) The Navy shall conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, acoustical 
monitoring team prior to the start of all pile driving activities, and 
when new personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    3. Mitigation Measures.
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Time Restrictions--For all in-water pile driving activities, 
the Navy shall operate only during daylight hours.
    (b) Use of Bubble Curtain.
    (i) The Navy shall employ a bubble curtain (or other sound 
attenuation device with proven typical performance of at least 8 dB 
effective attenuation) during impact pile driving of steel piles in 
water depths greater than 2 feet. In addition, the Navy shall implement 
the following performance standards.
    (ii) The bubble curtain must distribute air bubbles around 100 
percent of the piling perimeter for the full depth of the water column.
    (iii) The lowest bubble ring shall be in contact with the mudline 
for the full circumference of the ring, and the weights attached to the 
bottom ring shall ensure 100 percent mudline contact. No parts of the 
ring or other objects shall prevent full mudline contact.
    (iv) The Navy shall require that construction contractors train 
personnel in the proper balancing of air flow to the bubblers, and 
shall require that construction contractors submit an inspection/
performance report for approval by the Navy within 72 hours following 
the performance test. Corrections to the attenuation device to meet the 
performance standards shall occur prior to impact driving.
    (c) Use of Soft-Start.
    (i) The project shall utilize soft start techniques for impact pile 
driving.
    (ii) The Navy shall conduct an initial set of three strikes from 
the impact hammer at 40 percent energy, followed by a 1-minute waiting 
period, then two subsequent three strike sets.
    (iii) Soft start shall be required for any impact driving, 
including at the beginning of the day, and at any time following a 
cessation of impact pile driving of 30 minutes or longer.
    (d) Establishment of Shutdown Zones.
    (i) The shutdown zones pertaining specific species during impact 
driving and vibratory driving are shown on Tables 10, 1, and 12.
    (ii) If a marine mammal comes within or approaches the shutdown 
zone, pile driving operations shall cease.
    (iii) Pile driving and removal operations shall restart once the 
marine mammal is visibly seen leaving the zone or after 15 minutes have 
passed with no sightings.
    (iii) For in-water heavy machinery work other than pile driving 
(using, e.g.,standard barges, tug boats), if a marine mammal comes 
within 10 m, operations shall cease and vessels shall reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions.
    (iv) Shutdown shall occur if a species for which authorization has 
not been granted or for which the authorized numbers of takes have been 
met approaches or is observed within the pertinent take zone. The Navy 
shall then contact NMFS within 24 hours.
    (d) Establishment of Level A and B Harassment Zones.
    (i) The Level A and Level B zones pertaining to specific species 
during impact driving and vibratory driving are shown on Tables 12, 13, 
and 14.
    (e) Pile driving activities shall not be conducted when weather/
observer conditions do not allow for adequate sighting of marine 
mammals within the disturbance zone (e.g. lack of daylight/fog).
    (i) In the event of conditions that prevent the visual detection of 
marine mammals, impact pile driving already underway shall be 
curtailed, but vibratory driving may continue if driving has already 
been initiated on a given pile.
    4. Monitoring.
    The holder of this Authorization is required to conduct visual 
marine mammal monitoring during pile driving activities.
    (a) Visual Marine Mammal Observation--The Navy shall collect 
sighting data and behavioral responses to pile driving for marine 
mammal species observed in the region of activity during the period of 
activity. Visual monitoring shall include the following:
    (i) Marine Mammal Observers (MMOs) shall be positioned at the best 
practicable vantage points, taking into consideration security, safety, 
and space limitations. The MMOs shall be stationed in a location that 
shall provide adequate visual coverage for the shutdown zones.
    (ii) During pile driving, one MMO shall be stationed in a vessel, 
and at least four additional MMOs shall be stationed on the pier, along 
the shore, or on the pile driving barge to maximize observation 
coverage
    (iii) Monitoring shall be conducted by trained observers, who shall 
have no other assigned tasks during monitoring periods. Trained 
observers shall be placed at the best vantage point(s) practicable to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable through communication with the equipment operator. The 
Navy shall adhere to the following additional observer qualifications:

[[Page 10713]]

    (1) Independent observers (i.e., not construction personnel) are 
required.
    (2) At least one observer must have prior experience working as an 
observer.
    (3) Other observers may substitute education (degree in biological 
science or related field) or training for experience.
    (iv) Where a team of three or more observers are required, one 
observer shall be designated as lead observer or monitoring 
coordinator. The lead observer must have prior experience working as an 
observer.
    (v) The Navy shall submit observer CVs for approval by NMFS.
    (vi) Monitoring shall take place from 15 minutes prior to 
initiation of pile driving activity through 30 minutes post-completion 
of pile driving activity.
    (b) Hydroacoustic Monitoring.
    (i) If approved by the U.S. Fish and Wildlife Service, baseline 
sound measurements of steel pile driving shall occur prior to the 
implementation of noise attenuation. Impact pile driving without noise 
attenuation shall be limited to the number of piles necessary to obtain 
an adequate sample size.
    (ii) If the Navy elects to conduct in-situ acoustic monitoring to 
establish actual distances to the thresholds for a pile type and 
installation method, the radii of the pertaining zones may be adjusted 
according to collected data.
    (iii) Any proposed acoustical monitoring plan and any proposed 
revisions to zone radii must be pre-approved by NMFS.
    (iv) A final acoustic monitoring report shall be submitted to NMFS 
within 30 days of completing the monitoring.
    5. Reporting.
    (a) A draft marine mammal monitoring report shall be submitted to 
NMFS within 90 days after the completion of pile driving and removal 
activities or a minimum of 60 days prior to any subsequent IHAs. A 
final report shall be prepared and submitted to the NMFS within 30 days 
following receipt of comments on the draft report from the NMFS. A If 
no comments are received from NMFS within 30 days, the draft final 
report shall constitute the final report. If comments are received, a 
final report addressing NMFS comments must be submitted within 30 days 
after receipt of comments.
    (i) The report shall include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated marine mammal observation data sheets.
    (ii) The report shall include all items identified in information 
described in Section 4 of the Marine Mammal Monitoring Plan (Appendix D 
of the application.)
    (b) Reporting injured or dead marine mammals:
    (i) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA, 
such as serious injury, or mortality, the Navy shall immediately cease 
the specified activities and report the incident to the Office of 
Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator, NMFS. The report must include the following information:
    (1) Time and date of the incident;
    (2) Description of the incident;
    (3) Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    (4) Description of all marine mammal observations and active sound 
source use in the 24 hours preceding the incident;
    (5) Species identification or description of the animal(s) 
involved;
    (6) Fate of the animal(s); and
    (7) Photographs or video footage of the animal(s). Activities shall 
not resume until NMFS is able to review the circumstances of the 
prohibited take. NMFS shall work with the Navy to determine what 
measures are necessary to minimize the likelihood of further prohibited 
take and ensure MMPA compliance. The Navy may not resume their 
activities until notified by NMFS.
    (ii) In the event that the Navy discovers an injured or dead marine 
mammal, and the lead observer determines that the cause of the injury 
or death is unknown and the death is relatively recent (e.g., in less 
than a moderate state of decomposition), the Navy shall immediately 
report the incident to the Office of Protected Resources, NMFS, and the 
West Coast Regional Stranding Coordinator, NMFS. The report must 
include the same information identified in 5(b)(i) of this IHA. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS shall work with the Navy to determine whether additional 
mitigation measures or modifications to the activities are appropriate.
    (iii) In the event that the Navy discovers an injured or dead 
marine mammal, and the lead observer determines that the injury or 
death is not associated with or related to the activities authorized in 
the IHA (e.g., previously wounded animal, carcass with moderate to 
advanced decomposition, or scavenger damage), the Navy shall report the 
incident to the Office of Protected Resources, NMFS, and the West Coast 
Regional Stranding Coordinator, NMFS, within 24 hours of the discovery. 
The Navy shall provide photographs or video footage or other 
documentation of the stranded animal sighting to NMFS.
    6. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
Service Pier Extension project. Please include with your comments any 
supporting data or literature citations to help inform our final 
decision on the request for MMPA authorization.
    On a case-by-case basis, NMFS may issue a one-year renewal IHA 
without additional notice when (1) another year of identical or nearly 
identical activities as described in the Specified Activities section 
is planned, or (2) the activities would not be completed by the time 
the IHA expires and renewal would allow completion of the activities 
beyond that described in the Dates and Duration section, provided all 
of the following conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA; and
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted beyond the 
initial dates either are identical to the previously analyzed 
activities or include changes so minor (e.g., reduction in pile size) 
that the changes do not affect the previous analyses, take estimates, 
or mitigation and monitoring requirements;
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures remain the same and appropriate, 
and the original findings remain valid.

    Dated: March 6, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-04857 Filed 3-9-18; 8:45 am]
 BILLING CODE 3510-22-P