Notice2024-07676
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Navy Maintenance and Pile Replacement Project in Puget Sound, Washington
Primary source
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Published
April 11, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the United States Navy (Navy) for authorization to take marine mammals incidental to 2 years of construction activities associated with the Naval Facilities Engineering Command Northwest (NAVFAC NW) Maintenance and Pile Replacement (MPR) project in Puget Sound, Washington. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue two consecutive 1-year incidental harassment authorizations (IHAs) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorizations and agency responses will be summarized in the final notice of our decision.
Full Text
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[Federal Register Volume 89, Number 71 (Thursday, April 11, 2024)]
[Notices]
[Pages 25580-25608]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-07676]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD681]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to U.S. Navy Maintenance and Pile
Replacement Project in Puget Sound, Washington
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorizations; request
for comments on proposed authorizations and possible renewal.
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SUMMARY: NMFS has received a request from the United States Navy (Navy)
for authorization to take marine mammals incidental to 2 years of
construction activities associated with the Naval Facilities
Engineering Command Northwest (NAVFAC NW) Maintenance and Pile
Replacement (MPR) project in Puget Sound, Washington. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue two consecutive 1-year incidental harassment
authorizations (IHAs) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorizations and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than May 13,
2024.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources, NMFS
and should be submitted via email to <a href="/cdn-cgi/l/email-protection#f0b9a4a0deb69c959d999e97b09e9f9191de979f86"><span class="__cf_email__" data-cfemail="7c35282c523a10191115121b3c12131d1d521b130a">[email protected]</span></a>. 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:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In case of
problems accessing these documents, please call the contact listed
above.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> 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: Kate Fleming, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
[[Page 25581]]
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms cited above are included in the relevant sections
below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of two
consecutive IHAs) with respect to potential impacts on the human
environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed IHAs 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
request for two consecutive IHAs.
Summary of Request
On October 5, 2023, NMFS received a request from the Navy for two
consecutive 1-year IHAs to take marine mammals incidental to
construction associated with the Navy's NAVFAC NW MPR project in Puget
Sound, Washington. Following NMFS' review of the application, the Navy
submitted a revised version on December 14, 2023, additional
information on January 10, 2024, and the marine mammal monitoring plan
on January 23, 2024. Final revisions to both the application and the
marine mammal monitoring plan were provided on March 2, 2024. The
application was deemed adequate and complete on February 27, 2024. The
Navy's request is for take of 10 species of marine mammals by Level B
harassment and, for harbor seal, Level B and Level A harassment.
Neither the Navy nor NMFS expect serious injury or mortality to result
from this activity. Therefore, IHAs are appropriate.
NMFS previously issued a regulation and associated Letters of
Authorization to the Navy for related work (84 FR 15963, April 17,
2019; <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-marine-structure-maintenance-and-pile-replacement-wa">https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-marine-structure-maintenance-and-pile-replacement-wa</a>). The Navy complied with all the requirements (e.g.,
mitigation, monitoring, and reporting) of the previous LOAs, and
information regarding their monitoring results may be found in the
Effects of Specified Activities on Marine Mammals and Their Habitat.
Description of Proposed Activity
Overview
Maintaining existing wharfs and piers is vital to sustaining the
Navy's mission and ensuring readiness. To ensure continuance of
necessary missions at the four installations, the Navy must conduct
annual maintenance and repair activities at existing marine waterfront
structures, including removal and replacement of piles of various types
and sizes. The Navy refers to this program as the Marine Structure MPR
program.
The activities that have the potential to take marine mammals by
Level A harassment and Level B harassment include installation and/or
removal of timber, concrete, and steel piles by vibratory and impact
pile driving and down-the hole (DTH) drilling. Construction would span
the course of 2 years, with the first year beginning on July 15, 2024,
and lasting through July 14, 2025. The second year of construction
activities would begin July 15, 2025, and continue through July 14,
2026.
The Navy has requested the issuance of two consecutive IHAs in
association with the two project years. Given the similarities in
activities between project years, NMFS is issuing this single Federal
Register notice to solicit public comments on the issuance of the two
similar, but separate, IHAs.
Dates and Duration
The Navy anticipates that the planned NAVFAC NW MPR activities will
occur over 2 years. The year 1 IHA would be valid from July 1, 2024-
June 30, 2025, and the year 2 would span July 1, 2025-June 30, 2026.
The specified activities would occur at any time during each project
year, subject to existing time of year restrictions, or in-water work
windows, designed to protect fish species listed under the U.S.
Endangered Species Act (ESA). For Naval Base Kitsap (NBK) Bangor
(located in Hood Canal), in-water work would occur from July 16 through
January 15 each project year. At the remaining three facilities
(located in Puget Sound), in-water work would occur from July 16
through February 15.
Days of pile driving at each site were based on the estimated work
days using a slow production rate (e.g., four-six piles per day for
fender pile replacement). These conservative rates are the basis for
estimates of total days at each facility each year (table 1, table 2).
These totals include both extraction and installation of piles and
represent a conservative estimate of pile driving days at each
facility. In a real construction situation, pile driving production
rates would be maximized when possible and actual daily production
rates may be higher, resulting in fewer actual pile driving days.
Specific Geographic Region
The four installations are located within the inland waters of
Washington State. One facility is located within Hood Canal, while the
remainder are located within Puget Sound. See figure 1-1 of the Navy's
application for a regional map and section 2 for full details regarding
the specified geographical region. Puget Sound is one of the largest
estuaries in the United States and is a place of great physical and
ecological complexity and productivity. With nearly six million people
(doubled since the 1960s), Puget Sound is also heavily influenced by
human activity.
NBK Bangor serves as the Pacific homeport for the Navy's TRIDENT
submarine squadron and other ships home-ported or moored at the
installation and to maintain and operate administrative and personnel
support facilities including security, berthing, messing, and
recreational services. It is located on Hood Canal, a long, narrow,
fjord-like basin of western Puget Sound (see figure 1-2 of the Navy's
application). Oriented northeast to southwest, the portion of the canal
from Admiralty Inlet to a large bend, called the Great Bend, at
Skokomish, Washington, is 84 kilometers (km) (52 miles (mi)) long. East
of the Great Bend, the canal extends an additional 24 km (15 mi) to
Belfair. Throughout its 108-km (67 mi) length, the width of the canal
varies from 1.6 to 3.2 km (1 to 2 mi) and exhibits strong depth/
elevation gradients. Hood Canal is characterized by relatively steep
sides and irregular seafloor topography. In northern Hood Canal, water
depths in the center of the waterway near Admiralty Inlet vary between
91 and 128 meters (m) (300 and 420 feet (ft)). As the canal extends
southwestward toward the Olympic Mountain Range and Thorndyke Bay,
water depth decreases to approximately 49 m (160 ft) over a moraine
deposit. This deposit forms a sill across the canal
[[Page 25582]]
in the vicinity of Thorndyke Bay, which limits seawater exchange with
the rest of Puget Sound. The NBK Bangor waterfront occupies
approximately 8 km (5 mi) of the shoreline within northern Hood Canal
(1.7 percent of the entire Hood Canal coastline) and lies just south of
the sill feature.
NBK Bremerton serves as the homeport for a nuclear aircraft carrier
and other Navy vessels. It is located on the north side of Sinclair
Inlet in southern Puget Sound (see figure 1-3 of the Navy's
application). Sinclair Inlet is located off the main basin of Puget
Sound and is about 6.9 km long and 1.9 km wide. The inlet is connected
to the main basin through Port Orchard Narrows and Rich Passage.
Another relatively narrow waterway, Port Washington Narrows, connects
Sinclair Inlet to Dyes Inlet. In-water structures, shoreline fill, and
erosion protection at NBK Bremerton have resulted in a shoreline
geometry and character that is quite different from undisturbed
shorelines in Puget Sound. Bathymetry near existing piers and in
turning basins immediately offshore has been altered by significant
dredging to accommodate aircraft carriers and other Navy vessels. Water
depths range from 12 to 14 m (40 to 45 ft), increasing to 14 to 15 m
(45 to 50 ft) in dredged berthing areas. West of the project sites,
further into Sinclair Inlet, depths gradually decrease to less than 9 m
(30 ft).
NBK Manchester provides bulk fuel and lubricant support to area
Navy afloat and shore activities. It is located on Orchard Point,
approximately 6.4 km (4 mi) due east of Bremerton. Please see figure 1-
4 of the Navy's application. The installation is bounded by Clam Bay to
the northwest, Rich Passage to the northeast, and Puget Sound to the
east. NBK Manchester piers are located on the north side of Orchard
Point and in a small embayment open on the south side of Orchard Point.
In Clam Bay, the bathymetry is gently sloping with depths in the outer
portions of the bay of approximately 5.5 m (18 ft) below mean lower low
water (MLLW). Depths off Orchard Point drop off dramatically to 18 m
(60 ft) below MLLW approximately 150 m (500 ft) from shore and 90 m
(300 ft) below MLLW 1.6 km (1 m) offshore. Rich Passage is a shallow
sill, less than 21 m (70 ft) deep.
Naval Station (NS) Everett provides homeport ship berthing,
industrial support, and a Navy administrative center. It is located in
Port Gardner Bay in Puget Sound's Whidbey Basin (see figure 1-5 of the
Navy's application). To the west of the installation is the channelized
mouth of the Snohomish River bounded by Jetty Island, which is composed
of sediment from maintenance dredging and acts as a breakwater for the
northwest area along the installation's waterfront. Jetty Island
separates Port Gardner Bay and Possession Sound from the Snohomish
River channel. The mouth of the Snohomish River channel is a
historically industrialized area of highly modified shorelines and
dredged waterways that forms a protected harbor within Port Gardner
Bay. East of Jetty Island lies the Snohomish River estuary, consisting
of a series of interconnected sloughs that flow through the lowlands
east and north of the river's main channel. Water depths in Possession
Sound range from about 9 m (30 ft) near the industrialized shoreline in
Port Gardner to 180 m (600 ft) in mid-channel.
Detailed Description of the Specified Activity
The Navy plans to conduct maintenance and repair activities at
marine waterfront structures at the four aforementioned installations
within Puget Sound (Washington inland waters) and Hood Canal. Repairs
would include replacing up to 150 structurally unsound piles with 164
concrete or steel piles over a 1-year period (July 2024 through July
2025) at NBK Bremerton and NBK Manchester using impact and vibratory
pile driving and removal and DTH drilling; and replacing 130
structurally unsound piles over a 1-year period (July 2025-July 2026)
at NBK Bremerton, NBK Bangor and NS Everett using impact and vibratory
pile driving and removal.
Tables 1 and 2 provide a summary of pile types, sizes, and maximum
numbers of piles at each installation to be replaced over the two 1-
year MPR Program periods from July 2024-July 2025 and July 2025-July
2026, respectively. This estimate assumes all piles would be removed
and replaced with new piles. However, existing piles may be repaired in
place with no new piles installed and if replaced piles are larger than
existing piles, typically fewer piles are needed. Therefore, estimates
of replaced piles for each installation are a conservative
overestimate. These estimates also include temporary (or ``false
work'') piles that may be required during construction. Actual numbers
will depend on the number actually replaced and the size and type of
new piles installed.
The MPR program includes pile repair, extraction, and installation,
all of which may be accomplished through a variety of methods. However,
only pile extraction and installation using vibratory and impact pile
drivers and DTH drilling are expected to have the potential to result
in incidental take of marine mammals. Pile repair methods include
stubbing, wrapping, pile encapsulation, welding, or coating. These
processes do not involve pile driving and are not expected to have the
potential to result in incidental take of marine mammals. Pile removal
may be accomplished via vibratory extraction or via mechanical methods
such as cutting/chipping, clamshell removal, or direct pull. Four
primary methods of pile installation would be used: water jetting,
vibratory pile driving, impact pile driving, or DTH drilling. Noise
levels produced through mechanical extraction activities and water
jetting are not expected to exceed baseline levels produced by other
routine activities and operations at the four facilities, and any
elevated noise levels produced through these activities are expected to
be intermittent, of short duration, and with low peak values.
Therefore, only impact and vibratory pile driving, vibratory removal,
and DTH drilling are carried forward for further analysis.
Vibratory hammers, which can be used to either install or extract a
pile, contain a system of counter-rotating eccentric weights powered by
hydraulic motors, and are designed in such a way that horizontal
vibrations cancel out, while vertical vibrations are transmitted into
the pile. The pile driving machine is lifted and positioned over the
pile by means of an excavator or crane, and is fastened to the pile by
a clamp and/or bolts. The vibrations produced cause liquefaction of the
substrate surrounding the pile, enabling the pile to be extracted or
driven into the ground using the weight of the pile plus the hammer.
Impact hammers use a rising and falling piston to repeatedly strike a
pile and drive it into the ground. DTH drilling is a common method used
to drill holes through hard rock substrates. DTH drilling uses rotary
cutting percussion action using a button bit. In DTH drilling, the
drill pipe transmits the necessary feed force and rotation to the
hammer and bit, along with the compressed air used to actuate the
hammer and flush the cuttings.
[[Page 25583]]
Table 1--Pile Types and Maximum Anticipated Number To Be Replaced at Each Installation Between July 2024 and
July 2025
----------------------------------------------------------------------------------------------------------------
Days of
Pile size/type Method Number of Estimated piles per day installation
piles or removal
----------------------------------------------------------------------------------------------------------------
NBK Bremerton (Pier C and Pier 5)
----------------------------------------------------------------------------------------------------------------
13-inch Timber................... Removal, Vibratory 78 6 (up to 10)............ 30
or Pull
24-in Concrete Octagonal......... Installation, 25 4.......................
Impact
18-in x 18-inch square concrete.. Installation, 65 5.......................
Impact
----------------------------------------------------------------------------------------------------------------
NBK Manchester (Fuel Pier)
----------------------------------------------------------------------------------------------------------------
26-in Steel...................... Removal, Pull or 72 N/A..................... 37
Cut
24-in Concrete................... Installation, DTH 74 1-2.....................
or impact
----------------------------------------------------------------------------------------------------------------
Table 2--Pile Types and Maximum Anticipated Number To Be Replaced at Each Installation Between July 2025 and
July 2026
----------------------------------------------------------------------------------------------------------------
Days of
Pile size/type Method Number of Estimated installation
piles piles per day or removal
----------------------------------------------------------------------------------------------------------------
NBK Bangor Marginal Wharf
----------------------------------------------------------------------------------------------------------------
36-inch Steel......................... Removal, Vibratory or 78 4 36
Pull
Installation, Vibratory 78 4
or Impact
----------------------------------------------------------------------------------------------------------------
NBK Bremerton (Pier F)
----------------------------------------------------------------------------------------------------------------
24-in Steel........................... Removal, Vibratory 48 1-6 24
Installation, Vibratory 48
----------------------------------------------------------------------------------------------------------------
NS Everett (Pier A)
----------------------------------------------------------------------------------------------------------------
12-in Steel........................... Removal, Vibratory or 4 1-2 8
Cut
Installation, Vibratory 4 1-2
or Impact
----------------------------------------------------------------------------------------------------------------
Between July 2024 and July 2025, the following activities are
planned: (1) At NBK Bremerton, 25 13-inch (in) timber fender piles
would be removed at Pier C using vibratory pile driving or pulling and
replaced with 25 24-in concrete fender piles using impact pile driving.
At the same installation, 53 13-in timber piles would be vibratory
removed at Pier 5 and replaced with up to 65 18-in concrete piles using
impact pile driving. Impact pile driving at Pier 5 may occur at the
same time as vibratory pile driving at Pier C, though Pier 5 is
shielded from Pier C pile driving sound by Dry Dock 6, which is a solid
structure extending into Sinclair Inlet; and (2) At NBK Manchester a
total of 72 26-in steel piles would be removed and replaced with 74 24-
in concrete piles at the Fuel Pier. Concrete piles would be installed
using DTH drilling in areas with bedrock while impact pile driving
would be used if there is no bedrock.
Between July 2025 and July 2026, the following activities are
planned: (1) Up to 78 steel fender piles (36-in) at NBK Bangor are
anticipated to be removed by vibratory pile driving or cutting, and 78
steel fender piles (36-in) could be installed using vibratory pile
driving with impact proofing at this same location; (2) A total of 48
24-in steel fender piles would be removed and replaced with 48 new 24-
in steel fender piles using vibratory pile driving at NBK Bremerton,
Pier F; and (3) At NS Everett a total of 4 12-in steel piles will be
removed by vibratory pile driving or cutting and replaced with 4 12-in
steel piles by vibratory or impact pile driving if necessary at Pier A.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 3 lists all species or stocks for which take is expected and
proposed to be authorized for both proposed IHAs, and summarizes
information related to the population or stock, including regulatory
status under the MMPA and ESA and potential biological removal (PBR),
where known. PBR is defined by the MMPA as the maximum number of
animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population (as described in NMFS' SARs). While no
serious injury or mortality is anticipated or proposed to be authorized
here, PBR and annual serious injury and mortality from anthropogenic
sources are included here as gross indicators of the
[[Page 25584]]
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska and Pacific SARs. All values presented in table 3 are
the most recent available at the time of publication (including from
the draft 2023 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 3--Marine Mammal Species \4\ Likely To Be Affected by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. Eastern N Pacific...... -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Humpback Whale.................. Megaptera novaeangliae. Central America/ E, D, Y 1,494 (0.171, 1,284, 3.5 14.9
Southern Mexico--CA/OR/ 2021).
WA.
Mainland Mexico--CA/OR/ T, D, Y 3,477 (0.101, 3,185, 43 22
WA. 2018).
Hawai'i................ -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Minke Whale..................... Balaenoptera CA/OR/WA............... -, -, N 915 (0.792, 509, 2018) 4.1 0.19
acutorostrata.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Killer Whale.................... Orcinus orca........... Eastern North Pacific E, D, Y 73 (N/A, 73, 2022).... 0.13 0
Southern Resident.
West Coast Transient... -, -, N 349 \5\ (N/A, 349, 3.5 0.4
2018).
Family Phocoenidae (porpoises):
Dall's Porpoise................. Phocoenoides dalli..... CA/OR/WA............... -, -, N 16,498 (0.61, 10,286, 99 >=0.66
2018).
Harbor Porpoise................. Phocoena phocoena...... Washington Inland -, -, N 11,233 (0.37, 8,308, 66 >=7.2
Waters. 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
CA Sea Lion..................... Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >321
2014).
Steller Sea Lion................ Eumetopias jubatus..... Eastern................ -, -, N 36,308 \6\ (N/A, 2,178 93.2
36,308, 2022).
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... Washington Inland Hood -, -, N 3,363 (0.16, 2,940, 88 2
Canal. 2019).
Washington Northern -, -, N 16,451 (0.07, 15,462, 928 40
Inland Waters. 2019).
Northern Elephant Seal.......... Mirounga angustirostris CA Breeding............ -, -, N 187,386 (N/A, 85,369, 5,122 13.7
2013).
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\1\ 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 SARs online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>.
CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>).
\5\ Nest is based upon count of individuals identified from photo-ID catalogs in analysis of a subset of data from 1958-2018.
\6\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only.
As indicated above, all 10 species (with 14 managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species that could
potentially occur in the proposed project areas are included in table
3-1 of the application for two consecutive IHAs. While Pacific white-
sided dolphin, bottlenose dolphin, long-beaked common dolphin, and
Risso's dolphin have been documented in the Puget Sound, the temporal
and/or spatial occurrence of these species is such that take is not
expected to occur, and they are not discussed further beyond the
explanation provided here. Additionally, the range of the southern
Puget Sound stock of harbor seal does not overlap with the project area
and the stock is not discussed further. These species are very rare in
Puget Sound and are not expected to occur near any of the MPR
installations.
[[Page 25585]]
In addition, the northern sea otter may be found in the Puget Sound
area. However, northern sea otters are managed by the U.S. Fish and
Wildlife Service and are not considered further in this document.
Gray Whale
Gray whales are observed in Washington inland waters in all months
of the year, with peak numbers occurring from March through June
(Calambokidis et al., 2010). Most whales sighted are part of a small
regularly occurring group of 6 to 10 whales that use the northern Puget
Sound as a springtime feeding area (Calambokidis et al., 2010;
Calambokidis, 2017). Observed feeding areas are located in Saratoga
Passage between Whidbey and Camano Islands including Crescent Harbor,
and in Port Susan Bay located between Camano Island and the mainland
north of Everett (Calambokidis et al., 2010). Gray whales that are not
identified with the regularly occurring feeding group are occasionally
sighted in Puget Sound. These whales are not associated with feeding
areas and are often emaciated (WDFW, 2012).
In the waterways near NBK Bremerton (Rich Passage/Sinclair Inlet/
Dyes Inlet/Agate Passage), 11 opportunistic sightings of gray whales
were reported to the Orca Network (a public marine mammal sightings
database) between 2003 and 2012. In October 2020, PSOs observed a gray
whale near NBK Bangor during construction associated with a Pier
Extension Project (DoN, 2021). PSOs were on site observing marine
mammals for 99 days between July 2020 and January 2021 (DoN, 2021) and
for 32 days between October 2021 and January 2022 (DoN, 2022). However,
gray whales were not observed during monitoring efforts associated with
other projects occurring at relevant Navy installations in Puget Sound.
This includes two projects occurring at NBK Bangor: the Explosives
Handling Wharf Pile Replacement Project (monitoring occurred on 14 days
between August 2021 and October 2021) (Hamer Environmental, 2021), and
the Service Pier B710 Pile Replacement Project (monitoring occurred on
4 days between December 2021 and January 2022) (Sandoval et al., 2022),
and one project occurring at NBK Manchester in which PSOs monitored for
11 days between September and December 2021 for the Pier B213 Fender
Replacement Project (Sandoval and Johnson, 2021).
There is a Biologically Important Area (BIA) for migrating gray
whales in the inland waters of Puget Sound from January through July
and October through December and for feeding gray whales between March
and May (Calambokidis et al., 2015).
Between 2019 and 2023, there was an Unusual Mortality Event (UME)
for gray whales occurring along the West Coast from Mexico through
Alaska. While most of the strandings associated with this UME have been
documented along Washington's Pacific coast, 14 gray whale strandings
have been reported in inland waters between February and July, 2 of
which were reported near NS Everett (May 2019 and April 2020); one at
the mouth of Hood Canal (May 2019), and one near NBK Bremerton (March
2021). Additionally, a gray whale spent several weeks in Dyes Inlet
near NBK Bremerton in April and May 2023 and subsequently stranded near
Olympia, Washington in June of that year. Gray whales are rarely
sighted in Hood Canal south of the Hood Canal Bridge, including a
stranded whale at Belfair State Park (Orca Network, 2022).
Gray whales are expected to occur in the waters surrounding all
four installations. However, gray whales are expected to occur
primarily from March through June when in-water construction will not
occur. Therefore, although some exposure to individual gray whales
could occur at the four facilities, project timing will help to
minimize potential exposures.
Humpback Whale
On September 8, 2016, NMFS divided the once single species into 14
distinct population segments (DPS) under the ESA, removed the species-
level listing as endangered, and, in its place, listed four DPSs as
endangered and one DPS as threatened (81 FR 62259, September 8, 2016).
The remaining nine DPSs were not listed. There are four DPSs in the
North Pacific, including Western North Pacific and Central America,
which are listed as endangered, Mexico, which is listed as threatened,
and Hawaii, which is not listed.
The 2022 Pacific SARs described a revised stock structure for
humpback whales which modifies the previous stocks designated under the
MMPA to align more closely with the ESA-designated DPSs (Caretta et
al., 2023; Young et al., 2023). Specifically, the three previous North
Pacific humpback whale stocks (Central and Western North Pacific stocks
and a CA/OR/WA stock) were replaced by five stocks, largely
corresponding with the ESA-designated DPSs. These include Western North
Pacific and Hawaii stocks and a Central America/Southern Mexico-CA/OR/
WA stock (which corresponds with the Central America DPS). The
remaining two stocks, corresponding with the Mexico DPS, are the
Mainland Mexico-CA/OR/WA and Mexico-North Pacific stocks (Caretta et
al., 2023; Young et al., 2023). The former stock is expected to occur
along the west coast from California to southern British Columbia,
while the latter stock may occur across the Pacific, from northern
British Columbia through the Gulf of Alaska and Aleutian Islands/Bering
Sea region to Russia.
The Hawai[revaps]i stock consists of one demographically
independent population (DIP)--Hawai[revaps]i--Southeast Alaska/Northern
British Columbia DIP and one unit--Hawai[revaps]i--North Pacific unit,
which may or may not be composed of multiple DIPs (Wade et al., 2021).
The DIP and unit are managed as a single stock at this time, due to the
lack of data available to separately assess them and lack of compelling
conservation benefit to managing them separately (NMFS, 2023; NMFS,
2019; NMFS, 2022b). The DIP is delineated based on two strong lines of
evidence: genetics and movement data (Wade et al., 2021). Whales in the
Hawai[revaps]i--Southeast Alaska/Northern British Columbia DIP winter
off Hawai[revaps]i and largely summer in Southeast Alaska and Northern
British Columbia (Wade et al., 2021). The group of whales that migrate
from Russia, western Alaska (Bering Sea and Aleutian Islands), and
central Alaska (Gulf of Alaska excluding Southeast Alaska) to
Hawai[revaps]i have been delineated as the Hawai[revaps]i-North Pacific
unit (Wade et al., 2021). There are a small number of whales that
migrate between Hawai[revaps]i and southern British Columbia/
Washington, but current data and analyses do not provide a clear
understanding of which unit these whales belong to (Wade et al., 2021)
(Caretta et al., 2023; Young et al., 2023).
The Mexico--North Pacific unit is likely composed of multiple DIPs,
based on movement data (Martien et al., 2021; Wade, 2021, Wade et al.,
2021). However, because currently available data and analyses are not
sufficient to delineate or assess DIPs within the unit, it was
designated as a single stock (NMFS, 2023a; NMFS, 2019; NMFS, 2022c).
Whales in this stock winter off Mexico and the Revillagigedo
Archipelago and summer primarily in Alaska waters (Martien et al.,
2021; Carretta et al., 2023; Young et al., 2023).
Within U.S. west coast waters, three current DPSs may occur: The
Hawaii DPS (not listed), Mexico DPS (threatened), and Central America
DPS (endangered). According to Wade et al. (2021), the probability that
whales encountered in Washington waters are from a given DPS are as
follows: Hawaii, 69 percent; Mexico (CA-OR-WA), 25 percent; Central
America, 6 percent.
[[Page 25586]]
Humpback whales have been reported in the Puget Sound during every
month in 2022 (Orca Network, 2023). Most humpback whale sightings
reported since 2003 were in the main basin of Puget Sound with numerous
sightings in the waters between Point No Point and Whidbey Island,
Possession Sound, and southern Puget Sound in the vicinity of Point
Defiance. Some of the reported sightings were in the vicinity of NS
Everett and NBK Manchester. A few sightings of possible humpback whales
were reported by Orca Network in the waters near NBK Bremerton and
between January 2003 and December 2015. Humpback whales were sighted in
the vicinity of Manette Bridge in Bremerton in March and May 2016, and
May 2017 (Orca Network, 2017), and a carcass was found under a dock at
NBK Bremerton in June 2016 (Cascadia Research, 2016).
In Hood Canal, single humpback whales were observed for several
weeks in 2012 and in 2015 (Orca Network, 2022). Multiple sightings in
Hood Canal were reported in June 2019, February through May 2020, and
August 2021 (Orca Network, 2022). Prior to the 2012 sightings, there
were no confirmed reports of humpback whales entering Hood Canal (Orca
Network, 2022).
Humpback whales were not observed by protected species observers
(PSOs) during monitoring completed for Navy construction projects at
NBK Bangor (DoN, 2021; DoN, 2022; Hamer Environmental, 2021; Sandoval
et al., 2022) and NBK Manchester (Sandoval and Johnson, 2021; Sandoval
et al., 2022; Hamer Environmental, 2021). The number of humpback whales
potentially present near any of the four naval installations over the
project time period is expected to be low in any month.
Minke Whale
Sightings of minke whales in Puget Sound are infrequent, with
approximately 14 opportunistic sightings recorded south of the
Admiralty Inlet between 2005 and 2012, from March through October. In
recent years (2022 and 2023), possible sightings of a single minke
whale have been reported near NBK Bangor in September and October (the
Orca Network 2022 and 2023), and in 2021 and 2022, a few minke whale
sightings were reported south of Whidbey Island by the Pacific Whale
Watch Association (Gless and Krieger, 2023). However, minke whales were
not observed by PSOs during monitoring completed for Navy construction
projects at NBK Bangor (DoN, 2021; DoN, 2022; Hamer Environmental,
2021; Sandoval et al., 2022) and NBK Manchester (Sandoval and Johnson,
2021; Sandoval et al., 2022; Hamer Environmental, 2021) and the number
of minke whales potentially present near any of the four installations
is expected to be very low in any month and even lower in winter
months.
Killer Whale (Transient)
Groups of transient killer whales were observed for lengthy periods
in Hood Canal in 2003 (59 days) and 2005 (172 days) (London, 2006), but
were not observed again until 2016, when they were seen on a handful of
days between March and May (including in Dabob Bay). Transient killer
whales were observed by PSOs in December 2020 and December 2021 during
construction at NBK Bangor (DoN, 2021; DoN, 2022). Transient killer
whales have been seen infrequently near NBK Bremerton, including in
Dyes Inlet and Sinclair Inlet (e.g., sightings in 2010, 2013, 2015,
2022, and 2023) (Orca Network, 2023). Transient killer whales have
occasionally been observed transiting through Rich Passage near NBK
Manchester. In 2022, transient killer whales were observed in
Possession Sound near NS Everett.
West Coast transient killer whales most often travel in small pods
averaging four individuals (Baird and Dill, 1996); however, the most
commonly observed group size in Puget Sound (waters east of Admiralty
Inlet, including Hood Canal, through South Puget Sound and north to
Skagit Bay) from 2004 to 2010 was 6 whales (Houghton et al., 2015).
This is consistent with the mean group size of transient killer whales
observed by PSOs during monitoring for year 1 of the service pier
extension project at NBK Bangor in 2021 (DoN, 2021). Mean group size of
killer whales observed at this site during year 2 was 5 (DoN, 2022).
Transient killer whales were not observed by PSOs during monitoring
completed for other Navy construction projects completed at NBK Bangor
(Hamer Environmental, 2021; Sandoval et al., 2022) or NBK Manchester
(Sandoval and Johnson, 2021; Sandoval et al., 2022; Hamer
Environmental, 2021).
Killer Whale (Resident)
Southern Resident Killer Whales (SRKW) are expected to occur
occasionally in the waters surrounding all of the installations except
those in Hood Canal, where they have not been reported since 1995
(NMFS, 2006; 86 FR 41668, August 2, 2021). SRKW are rare near NBK
Bremerton, with the last confirmed sighting in Dyes Inlet in 1997.
Southern residents have been observed in Saratoga Passage and
Possession Sound near NS Everett. SRKW were not observed by PSOs during
construction activities occurring at NBK Manchester (Sandoval and
Johnson, 2021) and NBK Bangor (DoN, 2021; DoN, 2022; Hamer
Environmental, 2021; Sandoval et al., 2022).
The stock contains three pods (J, K, and L pods), with pod sizes
ranging from approximately 16 (in K pod) to 34 (in L pod) individuals.
Group sizes encountered can be smaller or larger if pods temporarily
separate or join together.
Critical habitat for SRKW, designated pursuant to the ESA and
revised in 2018 (80 FR 9366, March 5, 2018) includes three specific
areas: (1) Summer core area in Haro Strait and waters around the San
Juan Islands; (2) Puget Sound; and (3) Strait of Juan de Fuca. The
primary constituent elements essential for conservation of the habitat
are: (1) Water quality to support growth and development; (2) Prey
species of sufficient quantity, quality, and availability to support
individual growth, reproduction, and development, as well as overall
population growth; and (3) Passage conditions to allow for migration,
resting, and foraging. The Puget Sound segment of the designated
critical habitat for SRKW is defined as the area south of the Deception
Pass Bridge, west of the entrance to Admiralty Inlet, and north of the
Hood Canal Bridge. Although the three naval installations that fall
within this area are excluded from the area designated as Critical
Habitat under the ESA, they do contain the aforementioned Primary
Constituent Elements (PCEs). However, we note that water quality and
habitat for prey species is generally degraded in the vicinity of these
industrial environments relative to other areas contacting the PCEs
that may be less impacted (see Effects of Specified Activities on
Marine Mammals and Their Habitat section). SRKW have been observed in
this area in all seasons but most occurrence here (especially the J
pod) typically correlates with fall salmon runs (NMFS 2006).
Dall's Porpoise
Dall's porpoise are known to occur in Puget Sound, and have been
sighted as far south as Carr Inlet in southern Puget Sound and as far
north as Saratoga Passage, north of NS Everett (Nysewander et al.,
2005; WDFW, 2008). Dall's porpoise could also occasionally occur in
Hood Canal with the last observation in deeper water near NBK Bangor in
2008 (Tannenbaum et al., 2009). However, Dall's porpoise were not
observed during vessel line-transect
[[Page 25587]]
surveys and other monitoring efforts completed in Hood Canal (including
Dabob Bay) in 2011 (HDR, 2012). Dall's porpoises have not been
documented in the Rich Passage to Agate Passage area in the vicinity of
NBK Bremerton, but have been observed in Possession Sound near NS
Everett (primarily during winter) (Nysewander et al., 2005; WDFW,
2008). Dall's porpoises could be present in waters in the vicinity of
any of the installations considered here, and are considered more
likely to occur during winter months than summer months in groups of up
to 25 individuals. Dall's porpoise were not observed by PSOs during
monitoring associated with construction activities at NBK Bangor (Hamer
Environmental 2021, Sandoval et al., 2022; DoN, 2021; DoN 2022) and NBK
Manchester (Sandoval and Johnson, 2021).
Harbor Porpoise
Sightings of harbor porpoise in Hood Canal north of the Hood Canal
Bridge have increased in recent years (Evenson et al., 2016; Elliser et
al., 2021; Rone et al., 2024). Across three seasons, Jefferson (2016)
estimated 185 individuals in Hood Canal based on aerial surveys
completed in 2013-2015, and less than a decade later, Rone's (2024)
population estimates based on vessel based surveys completed in 2022-
2023 in Hood Canal ranged from 308 individuals in the winter to 1,385
individuals in the fall. Mean group size of harbor porpoises for each
survey season in the 2013-2016 aerial surveys was 1.7 (Smultea et al.,
2017) and similarly, 1.6 individuals per group in Hood Canal during
surveys completed in 2023 (Rone et al., 2024).
Information is available on harbor porpoise occurrence in Puget
Sound (Navy, 2019; Smultea et al., 2022) and more recently some limited
site-specific (within 500 meters) information is available for the Navy
installations (DoN, 2021; DoN, 2022; Sandoval and Johnson, 2022).
PSOs associated with a service pier extension project at NBK Bangor
monitored for 95 days between July 16, 2020 and January 13, 2021.
Harbor porpoise were observed each month during the monitoring period,
with peak numbers recorded in August. A total of 420 sightings of
harbor porpoise groups were recorded during this time (DoN, 2021). The
closest harbor porpoises came to the project site during pile driving
operations was 75 m. Harbor porpoise were also observed during year 2
of this project, which took place on 32 days between October 19, 2021
and January 14, 2022. Groups of harbor porpoise were observed on 12
occasions in October, December and January (DoN, 2022); Sightings were
estimated to be 8,000 m from the project site during pile driving
operations. However, porpoise sightings were notably absent in a 21
square kilometers (km\2\) area adjacent to the NBK Bangor within the
otherwise high-density region, during surveys completed to collect
fine-scale marine mammal occurrence data in Hood Canal (Rone et al.,
2024).
At NBK Manchester, a total of 17 harbor porpoise were detected by
PSOs associated with a fender pile replacement project at Manchester
Fuel Depot on 11 days between September 28, 2021 and December 10, 2021
(Sandoval and Johnson, 2022).
Finally, monitoring reports are not available for NS Everett, but
according to the Navy's application, harbor porpoises have been
observed infrequently at this installation. See IHA application).
California Sea Lion
California sea lions are typically present most of the year except
for mid-June through July in Washington inland waters, with peak
abundance between October and April (Navy, 2023). During summer months
and associated breeding periods, the inland waters are not considered a
high-use area by California sea lions, as they would be returning to
rookeries in California waters. However, as described below, surveys at
the naval installations indicate that a few individuals may remain
year-round (Navy, 2023).
The Navy conducts surveys at its installations in Puget Sound that
have sea lion haulouts. Specifically, California sea lion haul-outs
occur at NBK Bangor, NBK Bremerton, and NS Everett (though California
sea lions may haul out opportunistically at any location). California
sea lions have been documented during shore-based surveys at NBK Bangor
in Hood Canal since 2008 in all survey months, with as many as 320
individuals observed at one time (October 2018) hauled out on
submarines at Delta Pier and on Port Security Barrier (PSB) floats
(Navy, 2023). Additionally, California sea lions were observed
consistently at NBK Bangor during Navy construction projects: 557
California Sea Lions were observed across 99 days between July 2020 and
January 2021 (DoN, 2021); 57 were observed across 32 days between
October 2021 and January 2022 (DoN, 2022); 44 California Sea Lions were
observed across 14 days between August 2021 and October 2021 (Hamer
Environmental, 2021); and 3 were observed across 4 days between
December 2021 and January 2022, (Sandoval et al., 2022).
California sea lions have been documented on PSB floats during
shore- and boat-based surveys at NBK Bremerton since 2010, with as many
as 412 individuals hauled out at one time (October 2019) (Navy, 2023).
California sea lions have been documented during shore-based
surveys at NS Everett from 2012 to 2022 in all survey months, with as
many as 267 individuals hauled out at one time (April 2020) on PSB
floats.
California sea lions haul out on floating platforms in Clam Bay
approximately 0.5 mi (0.8 km) offshore from the Manchester Fuel Depot's
finger pier, and approximately 13 km (8 mi) from NBK Bremerton. PSO's
observed a total of 276 California Sea Lions at NBK Manchester across
11 monitoring days occurring between September and December 2021
(Sandoval and Johnson, 2021).
The Navy conducted surveys of sea lions on the floats from 2012
through 2016, and 2018 through 2022. In 2020, the surveys were expanded
to include Orchard Rocks, a haulout approximately 0.8 mi (1.3 km)
northeast of Manchester Fuel Depot that is available at lower tides.
Between 2012 and 2016, California sea lions were observed in every
survey month except July and August, with as many as 130 individuals
present in one survey in October 2014. Aerial surveys were conducted by
WDFW from March-April 2013, July-August 2013, November 2013, and
February 2014. These surveys detected California sea lions on the
floating platforms during all survey months except July, with up to 54
individuals present on one survey in November 2013. In 2018, the number
of sea lions decreased corresponding to the removal of floats. Numbers
subsequently increased following the reintroduction of floats in 2021.
During this time, California sea lions were observed on the floating
platforms during all survey months except July, with up to 212
individuals present on 1 survey in February 2022.
California sea lions are expected to be exposed to noise from
project activities at NBK's Bangor, Bremerton, Manchester, and NS
Everett because haul-outs are at these installations or nearby.
Exposure is estimated to occur primarily from August through the end of
the in-water work window in mid-January or mid-February.
Steller Sea Lion
Steller sea lions have been seasonally documented in shore-based
surveys at NBK Bangor in Hood Canal since 2008
[[Page 25588]]
with a maximum of 21 individuals observed in November 2019 (Navy,
2023). Surveys at NBK Bangor indicate Steller sea lions begin arriving
in September and depart by the end of May (Navy, 2023). Steller sea
lions were not observed at NBK Bangor during construction occurring on
14 days between August and October 2021 (Hamer Environmental, 2021), on
4 construction days occurring between December and January 2022
(Sandoval, 2022), or on 32 construction days between October and
January (DoN, 2022). However, 87 Steller sea lions were observed across
99 days between July and January 2021 (DoN, 2021).
Steller sea lions have not been detected during shore-based surveys
at NBK Bremerton since the surveys were initiated in 2010 (Navy, 2023).
A Steller sea lion was sighted on a float on the floating security
barrier during a vessel survey in 2012 (Lance, 2012 personal
communication) and others were detected during aerial surveys conducted
by WDFW (Jeffries, 2000).
Steller sea lions haul out on floating platforms in Clam Bay
approximately 0.5 mi (0.8 km) offshore from the NBK Manchester finger
pier, and approximately 8 mi (13 km) from NBK Bremerton. The number of
Steller sea lions in the vicinity of NBK Manchester is limited by the
variable size and availability of floating platforms in Clam Bay. As
discussed above, the Navy has conducted surveys of sea lions on the
floats since November 2012; however, no surveys were conducted
September 2013 through November 2013 and July 2017 through June 2018
(Navy, 2023). Steller sea lions were seen in all surveyed months except
for June, July, and August with as many as 43 individuals present in
September 2021.
Shore-based surveys conducted since July 2012 at NS Everett have
rarely detected Steller sea lions. However, occasional observations
have been reported from the PSB or in the Notch Basin, generally one at
a time (Navy, 2023). Other than these detections on the installation's
PSBs, the nearest known Steller sea lion haulout is 14 mi (23 km) away;
therefore, Steller sea lions are expected to be a rare occurrence in
waters off this installation during pile driving activities.
Harbor Seal
Harbor seals in Washington inland waters have been divided into
three stocks: Hood Canal, Northern Inland Waters, and Southern Puget
Sound. The range of the northern inland waters stock includes Puget
Sound north of the Tacoma Narrows Bridge, the San Juan Islands, and the
Strait of Juan de Fuca, while the southern Puget Sound stock range
includes waters south of the Tacoma Narrows Bridge. Therefore, animals
present at NBK Bremerton, NBK Manchester, and NS Everett are most
likely to be from the northern inland waters stock, while those present
at NBK Bangor are expected to be from the Hood Canal stock.
Harbor seals are expected to occur year-round at all installations
with the greatest numbers expected at installations with nearby haulout
sites. In Hood Canal, where NBK 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 mi (13 km) away. Vessel-based surveys conducted from
2007 to 2010 at NBK Bangor observed harbor seals in every month of
surveys (Agness & Tannenbaum, 2009; Tannenbaum et al., 2009, 2011).
Harbor seals were routinely seen during marine mammal monitoring for
the Navy's recent construction projects at this site (Hamer
Environmental, 2021; Sandoval et al., 2022; DoN, 2021; DoN, 2022).
Small numbers of harbor seals have been documented hauling out
opportunistically at NBK Bangor (e.g., on the PSB floats, wavescreen at
Carderock Pier, buoys, barges, marine vessels, and logs) and on man-
made floating structures. The largest number of harbor seals observed
in a single survey was 27 individuals in October 2018.
At NS Everett, Navy surveys were conducted regularly between 2012
and 2016, and again beginning in 2019, at which point surveys were
expanded to include the entire East Waterway. The largest number of
harbor seals observed in a single survey was 578 individuals in
September 2019 (Navy, 2023). However, log rafts were removed from the
East Waterway in the spring of 2022 and number of seals observed per
survey has decreased. Harbor seals occupy the waters and haulout sites
near NS Everett year-round. Harbor seal abundance is highest July
through October. Mother pup pairs have been observed at NS Everett each
summer since 2018, with a peak count of 96 pups observed in August
2021.
No haulouts have been identified at NBK Bremerton or Manchester.
Single harbor seals have been observed swimming in these areas or
hauled out on nearby rocks or on floats. The nearest documented
haulouts to NBK Bremerton are across Sinclair Inlet, approximately 0.7
mi (1.1 km) away, and according to the Navy's application, is estimated
to have less than 100 individuals (see IHA application). The nearest
documented haulout to NBK Manchester is Orchard Rocks Conservation Area
in Rich Passage, approximately 1.0 mi away. As discussed above, the
Navy began surveying this area in June 2020, which has led to a
dramatic increase in the number of harbor seals observed in proximity
to Manchester Fuel Depot. A total of 25 harbor seals were observed by
PSOs across 11 monitoring days occurring between September and December
2021 at this Naval installation (Sandoval and Johnson, 2021). The Navy
has counted up to 153 harbor seals hauled-out and in the water near
Orchard Rocks in June (Navy, 2023). Blakely Rocks is another known
haulout in the vicinity of NBK Manchester, located approximately 3.5 mi
away on the east side of Bainbridge Island. The haulout at Blakely
Rocks is estimated to have less than 100 individuals (Jeffries, 2012
personal communication).
Northern Elephant Seal
No haul-outs occur in Puget Sound with the exception of individual
elephant seals occasionally hauling out for two to four weeks to molt,
usually during the spring and summer and typically on sandy beaches
(Calambokidis and Baird, 1994). These animals are usually yearlings or
subadults and their haul-out locations are unpredictable. One male
subadult elephant seal was observed hauled out to molt at Manchester
Fuel Depot in 2004 and a northern elephant seal was observed north of
NBK Bangor in Hood Canal, from Kitsap Memorial Park in August 2020
(DoN, 2021). Northern elephant seals were not observed by PSOs during
the Navy's other construction activities occurring at NBK Bangor (Hamer
Environmental, 2021; Sandoval et al., 2022; DoN, 2021; DoN, 2022) or
NBK Manchester (Sandoval and Johnson, 2021). Although regular haul-outs
occur in the Strait of Juan de Fuca, the occurrence of elephant seals
in Puget Sound is unpredictable and rare.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
[[Page 25589]]
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in table 4.
Table 4--Marine Mammal Hearing Groups
(NMFS, 2018)
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al., 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Effects of Specified Activities on Marine Mammals and Their Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activity
can occur from impact pile driving, and vibratory pile driving and
removal in both years, and the use of DTH equipment in year 1 only.
These effects may result in Level A or Level B harassment of marine
mammals in the project area.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (American National Standards Institute
(ANSI), 1995). The sound level of an area is defined by the total
acoustical energy being generated by known and unknown sources. These
sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10 to 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 removal, and
use of DTH equipment (year 1 only). The sounds produced by these
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms,
impact pile driving) are typically transient, brief (less than 1
second), broadband, and consist of high peak sound pressure with rapid
rise time and rapid decay (ANSI, 1986; National Institute of
Occupational Safety and Health (NIOSH), 1998; NMFS, 2018). Non-
impulsive sounds (e.g., aircraft, machinery operations such as drilling
or dredging, vibratory pile driving, and active sonar systems) can be
broadband, narrowband or tonal, brief or prolonged (continuous or
intermittent), and typically do not have the high peak sound pressure
with rapid rise/decay time that impulsive sounds do (ANSI, 1995; NIOSH,
1998; NMFS, 2018). The distinction between these two sound types is
important because they have differing potential to cause physical
effects, particularly with regard to hearing (e.g., Ward 1997 in
Southall et al., 2007).
Three types of hammers would be used on this project: impact,
vibratory, and DTH (year 1 only). Impact hammers
[[Page 25590]]
operate by repeatedly dropping and/or pushing a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak Sound
Pressure Levels (SPLs) may be 180 dB or greater, but are generally 10
to 20 dB lower than SPLs generated during impact pile driving of the
same-sized pile (Oestman et al., 2009). Rise time is slower, reducing
the probability and severity of injury, and sound energy is distributed
over a greater amount of time (Nedwell and Edwards, 2002; Carlson et
al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into to the DTH hammer to increase speed of
progress through the substrate (i.e., it is similar to a ``hammer
drill'' hand tool). The sounds produced by the DTH method contain both
a continuous, non-impulsive component from the drilling action and an
impulsive component from the hammering effect. Therefore, we treat DTH
systems as both impulsive and continuous, non-impulsive sound source
types simultaneously.
Acoustic Effects
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal and DTH equipment is the
primary means by which marine mammals may be harassed from the Navy's
specified activities. In general, animals exposed to natural or
anthropogenic sound may experience behavioral, physiological, and/or
physical effects, ranging in magnitude from none to severe (Southall et
al., 2007). Generally, exposure to pile driving and removal and DTH
noise has the potential to result in behavioral reactions (e.g.,
avoidance, temporary cessation of foraging and vocalizing, changes in
dive behavior) and, in limited cases, auditory threshold shifts (TS).
Exposure to anthropogenic noise can also lead to non-observable
physiological responses such as an increase in stress hormones.
Additional noise in a marine mammal's habitat can mask acoustic cues
used by marine mammals to carry out daily functions such as
communication and predator and prey detection. The effects of pile
driving and removal and DTH noise on marine mammals are dependent on
several factors, including but not limited to sound type (e.g.,
impulsive vs. non-impulsive), the species, age and sex class (e.g.,
adult male vs. mother with calf), duration of exposure, the distance
between the pile and the animal, received levels, behavior at time of
exposure, and previous history with exposure (Wartzok et al., 2003;
Southall et al., 2007). Here we discuss physical auditory effects (TSs)
followed by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). The amount of TS is customarily expressed in dB. A
TS can be permanent or temporary. As described in NMFS (2018), there
are numerous factors to consider when examining the consequence of TS,
including, but not limited to, the signal temporal pattern (e.g.,
impulsive or non-impulsive), likelihood an individual would be exposed
for a long enough duration or to a high enough level to induce a TS,
the magnitude of the TS, time to recovery (seconds to minutes or hours
to days), the frequency range of the exposure (i.e., spectral content),
the hearing and vocalization frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal; e.g., Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB TS
approximates PTS onset (Ward et al., 1958; Ward et al., 1959; Ward,
1960; Kryter et al., 1966; Miller, 1974; Henderson et al., 2008). PTS
levels for marine mammals are estimates, because there are limited
empirical data measuring PTS in marine mammals (e.g., Kastak et al.,
2008), largely due to the fact that, for various ethical reasons,
experiments involving anthropogenic noise exposure at levels inducing
PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--NMFS defines TTS as a temporary,
reversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Based on data from
cetacean TTS measurements (Southall et al., 2007), a TTS of 6 dB is
considered the minimum TS clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al., 2000; Finneran et al., 2000; Finneran et al., 2002).
As described in Finneran (2016), marine mammal studies have shown the
amount of TTS increases with cumulative sound exposure level
(SEL<INF>cum</INF>) in an accelerating fashion: At low exposures with
lower SEL<INF>cum,</INF> the amount of TTS is typically small and the
growth curves have shallow slopes. At exposures with higher
SEL<INF>cum,</INF> the growth curves become steeper and approach linear
relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in Masking,
below). For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that takes place during a time when the animal is traveling
through the open ocean, where ambient noise is lower and there are not
as many competing sounds present. Alternatively, a larger amount and
longer duration of TTS sustained during time when communication is
critical for successful mother/calf interactions could have more
serious impacts. We note that reduced hearing sensitivity as a simple
function of aging has been observed in marine mammals, as well as
humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
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 five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and
[[Page 25591]]
harbor porpoises have a lower TTS onset than other measured pinniped or
cetacean species (Finneran, 2015). Additionally, the existing marine
mammal TTS data come from a limited number of individuals within these
species. No data are available on noise-induced hearing loss for
mysticetes. For summaries of data on TTS in marine mammals or for
further discussion of TTS onset thresholds, please see Southall et al.
(2007), Finneran and Jenkins (2012), Finneran (2015), and table 5 in
NMFS (2018).
Activities for this project include impact and vibratory pile
driving, vibratory pile removal, and DTH drilling. There would likely
be pauses in activities producing the sound during each day. Given
these pauses and the fact that many marine mammals are likely moving
through the project areas and not remaining for extended periods of
time, the potential for TS declines.
Behavioral 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). 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). Animals are most likely to habituate to sounds
that are predictable and unvarying. 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.
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007;
Melc[oacute]n et al., 2012). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Wensveen et al., 2017). An
evaluation of whether foraging disruptions would be likely to incur
fitness consequences considers temporal and spatial scale of the
activity in the context of the available foraging habitat and, in more
severe cases may necessitate consideration of 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.
Respiration naturally varies with different behaviors, and
variations in respiration 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 also have shown that species and
signal characteristics are important factors in whether respiration
rates are unaffected or change, 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., 2005; Kastelein et al., 2006;
Kastelein et al., 2018; Gailey et al., 2007; Isojunno et al., 2018).
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 (Orcinus
orca) 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., 2007; Rolland et al., 2012). In some
cases, however, animals may cease or alter sound production in response
to underwater sound (e.g., Bowles et al., 1994; Castellote et al.,
2012; Cerchio et al., 2014).
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
[[Page 25592]]
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 airgun surveys (Malme et
al., 1984). Often avoidance is temporary, and animals return 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 observed in marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates and efficiency (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).
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 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive 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.
To assess the strength of behavioral changes and responses to
external sounds and SPLs associated with changes in behavior, Southall
et al. (2007) developed and utilized a severity scale, which is a 10-
point scale ranging from no effect (labeled 0), effects not likely to
influence vital rates (low; labeled from 1 to 3), effects that could
affect vital rates (moderate; labeled from 4 to 6), to effects that
were thought likely to influence vital rates (high; labeled from seven
to nine). Southall et al. (2021) updated the severity scale by
integrating behavioral context (i.e., survival, reproduction, and
foraging) into severity assessment. For non-impulsive sounds (i.e.,
similar to the sources used during the proposed action), data suggest
that exposures of pinnipeds to sources between 90 and 140 dB
(referenced to 1 micropascal (re 1 [mu]Pa)) do not elicit strong
behavioral responses; no data were available for exposures at higher
received levels for Southall et al. (2007) to include in the severity
scale analysis. Reactions of harbor seals were the only available data
for which the responses could be ranked on the severity scale. For
reactions that were recorded, the majority (17 of 18 individuals/
groups) were ranked on the severity scale as a 4 (defined as moderate
change in movement, brief shift in group distribution, or moderate
change in vocal behavior) or lower. The remaining response was ranked
as a six (defined as minor or moderate avoidance of the sound source).
The Navy documented marine mammals during construction activities
at NBK Manchester (September 28 and December 10, 2021) and NBK Bangor
(2021 and 2022) during work that preceded these proposed IHAs as well
as during the installation of a service pier. Harbor seals were
consistently the most frequently observed marine mammal in the area
observed by PSOs. During pile driving activities at these
installations, harbor seals were most commonly observed typically
traveling and swimming, though some behaviors recorded during pile
driving activities indicated that harbor seals were aware of the
construction, such as less foraging reported and looking at the
construction site or startling. Likewise California sea lions were
observed traveling and swimming during pile driving activities, but in
a couple instances were observed porpoising or breaching. Harbor
porpoises were observed traveling, milling, porpoising and a gray whale
was observed slow and fast traveling and milling. At NBK Bangor, a
total of three harbor seals were observed foraging, socializing,
feeding (when fish kills were apparent) during impact pile driving.
Behavior changes noted during pile driving included startle responses,
splashing, swimming in circles, re-entering water after being hauled
out and looking in all directions and swimming fast.
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
[[Page 25593]]
glycogen stores that can be quickly replenished once the stress is
alleviated. In such circumstances, the cost of the stress response
would not pose serious fitness consequences. However, when an animal
does not have sufficient energy reserves to satisfy the energetic costs
of a stress response, energy resources must be diverted from other
functions. This state of distress will last until the animal
replenishes its energetic reserves sufficient to restore normal
function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
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., pile
driving, shipping, sonar, seismic exploration) in origin. The ability
of a noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions. Masking of
natural sounds can result when human activities produce high levels of
background sound at frequencies important to marine mammals.
Conversely, if the background level of underwater sound is high (e.g.,
on a day with strong wind and high waves), an anthropogenic sound
source would not be detectable as far away as would be possible under
quieter conditions and would itself be masked.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA. Airborne noise would primarily be
an issue for pinnipeds that are swimming or hauled out near the project
site within the range of noise levels elevated above the acoustic
criteria. We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
likely previously have been `taken' because of exposure to underwater
sound above the behavioral harassment thresholds, which are generally
larger than those associated with airborne sound. Thus, the behavioral
harassment of these animals is already accounted for in these estimates
of potential take. Therefore, we do not believe that authorization of
additional incidental take resulting from airborne sound for pinnipeds
is warranted, and airborne sound is not discussed further.
Anticipated Effects on Marine Mammal Habitat
The Navy's construction activities could have localized, temporary
impacts on marine mammal habitat and their prey by increasing in-water
sound pressure levels and slightly decreasing water quality. Increased
noise levels may affect acoustic habitat (see masking discussion above)
and adversely affect marine mammal prey in the vicinity of the project
areas (see discussion below). During DTH, impact and vibratory pile
driving or removal, elevated levels of underwater noise would ensonify
a portion of Puget Sound (Year 1 and Year 2) and Hood Canal (Year 2
only) where both fishes and mammals occur and could affect foraging
success. Additionally, marine mammals may avoid the area during
construction, however, displacement due to noise is expected to be
temporary and is not expected to result in long-term effects to the
individuals or populations. Construction activities are of short
duration and would likely have temporary impacts on marine mammal
habitat through increases in underwater sound.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the area where piles are
installed and removed. In general, turbidity associated with the pile
installation is localized to about 25-ft (7.6 m) 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 pinnipeds could avoid localized areas of turbidity. Therefore, the
impact from increased turbidity levels is expected to be minimal for
marine mammals. Furthermore, pile driving and removal at the project
site would not obstruct movements or migration of marine mammals.
In-Water Construction Effects on Potential Foraging Habitat--The
areas likely impacted by the project are relatively small compared to
the available habitat in Puget Sound (Year 1 and Year 2) and Hood Canal
(Year 2 only). The total seafloor area affected by pile installation
and removal is a small area compared to the vast foraging area
available to marine mammals in the area. At best, the impacted areas
provide marginal foraging habitat for marine mammals and fishes.
Furthermore, pile driving and removal at the project site would not
obstruct long-term movements or migration of marine mammals.
Avoidance by potential prey (i.e., fish or, in the case of
transient killer whales, other marine mammals) of the immediate area
due to the temporary loss of this foraging habitat is also possible.
The duration of fish and marine mammal avoidance of this area after
pile driving stops is unknown, but a rapid return to normal
recruitment, distribution, and behavior is
[[Page 25594]]
anticipated. Any behavioral avoidance by fish or marine mammals of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity.
Effects on Potential Prey--Construction activities would produce
continuous (i.e., vibratory pile driving and DTH drilling) and
intermittent (i.e., impact driving and DTH drilling) sounds. Sound may
affect marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey varies by species, season, and
location. Here, we describe studies regarding the effects of noise on
known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fish; several are based on studies in support of large,
multiyear bridge construction projects (e.g., Scholik and Yan, 2001;
Scholik and Yan, 2002; Popper and Hastings, 2009). Several studies have
demonstrated that impulse sounds might affect the distribution and
behavior of some fishes, potentially impacting foraging opportunities
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012;
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999;
Paxton et al., 2017). However, some studies have shown no or slight
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al.,
2001; Jorgenson and Gyselman, 2009).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4 to 6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual
fish is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fishes from pile driving activities at
the project area would be temporary behavioral avoidance of the area.
The duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the expected
short daily duration of individual pile driving events and the
relatively small areas being affected. It is also not expected that the
industrial environment of the Navy installations provides important
fish habitat or harbors significant amount of forage fish.
The area likely impacted by the activities is relatively small
compared to the available habitat in inland waters in the region. Any
behavioral avoidance by fish of the disturbed area would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity. As described in the preceding, the potential for
Navy construction to affect the availability of prey to marine mammals
or to meaningfully impact the quality of physical or acoustic habitat
is considered to be insignificant. Effects to habitat will not be
discussed further in this document.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHAs, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., impact and vibratory pile driving and
removal and DTH drilling) has the potential to result in disruption of
behavioral patterns for individual marine mammals. There is also some
potential for auditory injury (Level A harassment) to result, primarily
for phocids because predicted auditory injury zones are larger than for
mid-frequency cetacean species and/or otariids, and they can be
difficult to detect. Auditory injury is unlikely to occur for mid, low,
and high-frequency cetacean species and otariids. The proposed
mitigation and monitoring measures are expected to minimize the
severity of the taking to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
[[Page 25595]]
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (c) of 120 dB (re 1 [mu]Pa) for
continuous (e.g., vibratory pile driving, drilling) and above RMS SPL
160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., seismic airguns)
or intermittent (e.g., scientific sonar) sources. Generally speaking,
Level B harassment take estimates based on these behavioral harassment
thresholds are expected to include any likely takes by TTS as, in most
cases, the likelihood of TTS occurs at distances from the source less
than those at which behavioral harassment is likely. TTS of a
sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that would not otherwise occur.
The Navy's proposed activity includes the use of continuous
(vibratory pile driving and removal and DTH drilling) and impulsive
(impact pile driving and DTH drilling) sources, and therefore the RMS
SPL thresholds of 120 and 160 dB re 1 [mu]Pa is applicable,
respectively.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). The Navy's
proposed activity includes the use of impulsive (impact pile driving
and DTH drilling) and non-impulsive (vibratory pile driving and
removal) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW)(Underwater)...... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW)(Underwater)..... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and SELcum (LE) has a reference value of
1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect ANSI standards (ANSI, 2013). However,
peak sound pressure is defined by ANSI as incorporating frequency weighting, which is not the intent for this
Technical Guidance. Hence, the subscript ``flat'' is being included to indicate peak sound pressure should be
flat weighted or unweighted within the generalized hearing range. The subscript associated with SELcum
thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and
PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The SELcum thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss (TL)
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal and
DTH drilling).
The project includes vibratory pile installation and removal,
impact pile driving, and DTH drilling in year 1 and vibratory pile
installation and removal and impact pile driving in year 2. Source
levels for these activities are based on reviews of measurements of the
same or similar types and dimensions of piles available in the
literature. Source levels for each pile size and activity each year are
presented in table 6. Source levels for vibratory installation and
removal of piles of the same diameter are assumed to be the same.
NMFS recommends treating DTH systems as both impulsive and
continuous, non-impulsive sound source type simultaneously. Thus,
impulsive thresholds are used to evaluate Level A harassment, and
continuous thresholds are used to evaluate Level B harassment. With
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A
harassment based on available data
[[Page 25596]]
regarding DTH systems of similar sized piles and holes (Heyvaert and
Reyff, 2021) (table 1, table 7 and table 8 includes number of piles and
duration each year; table 6 includes sound pressure and sound exposure
levels for each pile type).
The Navy proposed to use bubble curtains when impact driving steel
piles (relevant to Year 2 activities only). For the reasons described
in the next paragraph, we assume here that use of the bubble curtain
would result in a reduction of 8 dB from the assumed SPL (rms) and SPL
(peak) source levels for these pile sizes, and reduce the applied
source levels accordingly.
During the 2023 study at NBK Bremerton, the Navy conducted
comparative measurements of source levels when impact driving steel
piles with and without a bubble curtain. Underwater sound levels were
measured at two locations during the installation of one 24-in diameter
steel pile and four 36-in steel piles. The bubble curtain used during
the measurements reduced median peak sound levels by between 8 and 12
dB, median RMS sound levels by 10 and 12 dB, and median single strike
SEL sound levels by 7 and 8 dB. The analysis included in the proposed
rule for the regulations preceding these IHAs (83 FR 9366, March 5,
2018) as well as results from the NBK Bangor Trident Support Facilities
Explosive Handling Wharf study (Navy 2013), are consistent with these
findings. While proper set-up and operation of the system is critical,
and variability in performance should be expected, we believe that in
the circumstances evaluated here an effective attenuation performance
of 8 dB is a reasonable assumption.
Table 6--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, DTH Drilling, and Vibratory Pile Removal for
Year 1 and Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile driving method Pile type Pile size dB RMS dB Peak dB SEL Attenuation Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.......................... Concrete.......... 18-in........... 170 184 159 N/A.................. Navy 2015.
24-in........... 174 188 164 N/A.................. Navy 2015.
Vibratory....................... Timber............ 13-in........... 161 N/A N/A N/A.................. Greenbusch Group,
Inc. 2019.
DTH............................. Concrete.......... 24-in........... 167 184 159 N/A.................. Heyvaert & Reyff
2021.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.......................... Steel \1\......... 12.............. 177 192 167 -8 dB \1\............ Caltrans 2015,
36.............. 194 211 181 -8 dB \1\............ 2020.
Navy 2015b.
Vibratory....................... 12.............. 153 N/A N/A N/A.................. Navy 2015b.
24.............. 161 N/A N/A N/A.................. Navy 2015b.
36.............. 166 N/A N/A N/A.................. Navy 2015b.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; DTH = down-the-hole drilling; rms = root mean square; SEL = sound exposure level.
\1\ Values modeled for impact driving of 12-inch and 36-inch steel piles will be reduced by 8 dB for noise exposure modeling to account for attenuation
from a bubble curtain
TL is the decrease in acoustic intensity as an acoustic pressure
wave propagates out from a source. TL parameters vary with frequency,
temperature, sea conditions, current, source and receiver depth, water
depth, water chemistry, and bottom composition and topography. The
general formula for underwater TL is:
TL = B * Log10 (R1/R2),
where
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for the Puget Sound are not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically overestimates of
some degree, which may result in an overestimate of potential take by
Level A harassment. However, this optional tool offers the best way to
estimate isopleth distances when more sophisticated modeling methods
are not available or practical. For stationary sources such as pile
driving, the optional User Spreadsheet tool predicts the distance at
which, if a marine mammal remained at that distance for the duration of
the activity, it would be expected to incur PTS. Inputs used in the
optional User Spreadsheet tool, and the resulting estimated isopleths,
are reported below.
Table 7--User Spreadsheet Inputs, Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Impact DTH
--------------------------------------------------------------------------------------------------------------------------
13-in Timber 18-in Concrete 24-in Concrete 24-in Concrete
--------------------------------------------------------------------------------------------------------------------------
Installation or removal Installation Installation Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used......... A.1) Vibratory Pile Driving...... E.1) Impact Pile Driving...... E.1) Impact Pile Driving...... E.2) DTH Drilling.
Source Level (SPL)........... 161 RMS.......................... 159 SEL....................... 164 SEL....................... 167 RMS, 159 SEL.
Transmission Loss Coefficient 15............................... 15............................ 15............................ 15.
[[Page 25597]]
Weighting Factor Adjustment 2.5.............................. 2............................. 2............................. 2.
(kHz).
Activity Duration per day 90............................... .............................. .............................. 80.
(minutes).
Strike Rate per second....... ................................. .............................. .............................. 12.
Number of strikes per pile... ................................. 1,000......................... 1,000.........................
Number of piles per day...... 6................................ 5............................. 4............................. 2.
Distance of sound pressure 10............................... 10............................ 10............................ 10.
level measurement.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 8--User Spreadsheet Inputs, Year 2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Impact
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
12-in Steel 24-in Steel 36-in Steel 12-in Steel; BC 36-in Steel; BC
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
Installation or removal Installation or removal Installation or removal Installation Installation
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.......... A.1) Vibratory Pile Driving..... A.1) Vibratory Pile Driving..... A.1) Vibratory Pile Driving..... E.1) Impact Pile Driving.... E.1) Impact Pile Driving.
Source Level (SPL)............ 153 RMS......................... 161 RMS......................... 166 RMS......................... 167 SEL..................... 181 SEL.
Transmission Loss Coefficient. 15.............................. 15.............................. 15.............................. 15.......................... 15.
Weighting Factor Adjustment 2.5............................. 2.5............................. 2.5............................. 2........................... 2.
(kHz).
Activity Duration per day 30.............................. 90.............................. 133............................. N/A......................... N/A.
(minutes).
Number of strikes per pile.... N/A............................. N/A............................. N/A............................. 1,000....................... 1,000.
Number of piles per day....... 2............................... 6............................... 4............................... 2........................... 4.
Distance of sound pressure 10.............................. 10.............................. 10.............................. 10.......................... 10.
level measurement.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
BC = Bubble Curtain
Table 9--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving and DTH
drilling
----------------------------------------------------------------------------------------------------------------
Level A harassment isopleths (m) Level B
--------------------------------------------- harassment Area of harassment
Pile type isopleth zone (km\2\)
LF MF HF PW OW (m)
----------------------------------------------------------------------------------------------------------------
Year 1
Vibratory
----------------------------------------------------------------------------------------------------------------
13-inch timber.................. 8.9 <1 13.2 5.4 <1 5,412 16 km\2\.
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
18-inch concrete................ 73.3 2.6 87.4 39.3 2.9 46 0.007 km\2\.
24-inch concrete................ 136.2 4.8 162.2 72.9 5.3 86 0.02 km\2\.
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
24-inch concrete................ 374.1 13.3 445.6 200.2 14.6 13,594 75 km\2\.
----------------------------------------------------------------------------------------------------------------
Year 2
Vibratory
----------------------------------------------------------------------------------------------------------------
12-inch steel................... 1.3 <1 <1 <1 <1 1,585 8 km\2\.
24-inch steel................... 8.9 <1 13.2 5.4 <1 5,412 16 km\2\.
36-inch steel................... 25.1 2.2 37.0 15.2 1.1 11,659 31 km\2\.
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
12-inch steel................... 39.8 1.4 47.4 21.3 1.6 39.8 0.005 km\2\.
[[Page 25598]]
36-inch steel................... 542.1 19.3 645.8 290.1 21.1 541.2 0.92 km\2\.
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations.
Available information regarding marine mammal occurrence in the
vicinity of the four installations includes density information
aggregated in the Navy's Marine Mammal Species Density Database (NMSDD;
Navy, 2019) or site-specific survey information from particular
installations (e.g., local pinniped counts). More recent density
estimates for harbor porpoise are available in Smultea et al. (2017)
and Rone et al., (2024). First, for each installation we describe
anticipated frequency of occurrence and the information deemed most
appropriate for the exposure estimates. For all facilities, large
whales (humpback whale, minke whale, and gray whale), killer whales
(transient and resident), Dall's porpoise, and elephant seal are
considered as occurring only rarely and unpredictably, on the basis of
past sighting records. For these species, average group size is
considered in concert with expected frequency of occurrence to develop
the most realistic exposure estimate. Although certain species are not
expected to occur at all at some facilities--for example, resident
killer whales are not expected to occur in Hood Canal--the Navy has
developed an overall take estimate and request for these species for
each project year.
All species described above are considered as rare, unpredictably
occurring species. A density-based analysis is used for harbor porpoise
(table 10), while data from site-specific abundance surveys are used
for California sea lion, Steller sea lion, and harbor seal at all
installations. One exception is that for Steller sea lion at NBK
Bremerton, a density-based analysis is used because local data have
resulted in no observations of this species (Navy, 2023).
Table 10--Marine Mammal Densities
----------------------------------------------------------------------------------------------------------------
Density (June-
Species Region February)
----------------------------------------------------------------------------------------------------------------
Harbor porpoise................................ Hood Canal (Bangor)......................... \1\ 0.81
East Whidbey Island (Everett)............... \2\ 0.75
Sinclair Inlet (Bremerton).................. \2\ 0.53
Vashon (Manchester)......................... \2\ 0.25
Steller Sea Lion............................... Puget Sound--Fall/Winter.................... \3\ 0.05
----------------------------------------------------------------------------------------------------------------
Sources: \1\ Rone et al., 2024; \2\ Smultea et al., 2017; \3\ Navy, 2019.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
To quantitatively assess exposure of marine mammals to noise from
pile driving activities, the Navy proposed three methods, to be used
depending on the species' assumed spatial and temporal occurrence. For
species with rare or infrequent occurrence at a given installation
during the in-water work window, the likelihood of interaction was
reviewed on the basis of past records of occurrence (described in
Description of Marine Mammals in the Area of Specified Activities) and
the potential maximum duration of work days at each installation, as
well as total work days for all installations. Occurrence of the
species in this category [i.e., large whales, killer whales, elephant
seal (all installations), and Dall's porpoise (Hood Canal only)] would
not be anticipated to extend for multiple days. Except for SRKW, the
probable duration of all rare, unpredictably occurring species is
assumed to be two days, roughly equivalent to one transit in and out of
a project site. In the case of SRKW, the probable duration is assumed
to be one day only, as SRKW have not been observed near naval
installations during work completed previously at these installations.
The calculation for species with rare or infrequent occurrence is:
Exposure estimate = expected group size x probable duration
For species that occur regularly but for which site-specific
abundance information is not available, density estimates (table 10)
were used to determine the number of animals potentially exposed on any
one day of pile driving or removal. The calculation for density-based
analysis of species with regular occurrence is:
Exposure estimate = N (density) x Zone of Influence (ZOI, area) x days
of pile driving
For remaining species, site-specific abundance information (i.e.,
primarily the mean of monthly average counts per surveys completed
between 2008 and 2022) was used. In cases where documented presence of
a given pinniped species was variable throughout year and the mean of
monthly average count (2008-2022) was [gteqt]1, the mean of monthly
maximum counts of surveys completed between 2008 and 2022 was used:
Exposure estimate = Abundance x days of pile driving
Large Whales--For each species of large whale (i.e., humpback
whale, minke whale, and gray whale), we assume rare and infrequent
occurrence at all installations. For all three species, if observed,
they typically occur singly or in pairs. Therefore, for all three
species, we assume that a pair of whales may occur in the vicinity of
an
[[Page 25599]]
installation for a total of two days. We do not expect that this would
happen multiple times, and cannot predict where such an occurrence may
happen, so propose to authorize take by Level B harassment of four of
each large whale species each project year.
It is important to note that the Navy proposes to implement a
shutdown of pile driving activity if any large whale is observed within
any defined harassment zone (see Proposed Mitigation). Therefore, the
proposed IHA is intended to provide insurance against the event that
whales occur within Level B harassment zones that cannot be fully
observed by monitors. As a result of this proposed mitigation, we do
not believe that Level A harassment is a likely outcome upon occurrence
of any large whale. The calculated Level A harassment zone is a maximum
of 374 m for DTH installation of 24-in concrete piles in year 1 and 542
m for impact installation of 36-in steel piles with a bubble curtain in
year, and this requires that a whale be present at that range for the
full duration of 1,000 pile strikes. Given the Navy's commitment to
shut down upon observation of a large whale in any harassment zone, and
the likelihood that the presence of a large whale in the vicinity of
any Navy installation would be known due to reporting via Orca Network,
we do not expect that any whale would be present within a Level A
harassment zone for sufficient duration to actually experience PTS.
Killer Whales--For transient killer whales, the proposed take
authorization is derived via the same process described above for large
whales: we assume an average group size of six whales occurring for a
period of 2 days. The resulting total proposed authorization of take by
Level B harassment of 12 for transient killer whales would also account
for the low probability that a larger group occurred once. For SRKW, we
assume an average group size of 20 whales occurring within the Level B
harassment zone on one day each year. A group of 20 SRKW closely
represents the average size of the pod most likely to occur near a Navy
installation (the J pod), and corresponds to 75 percent of the average
of all 3 pods that make up the stock. SRKW have not been observed near
naval installations during work completed previously at these
installations.
Similar to large whales, the Navy plans to implement shutdown of
pile driving activity at any time that any killer whale is observed
within any calculated harassment zone. We expect this to minimize the
extent and duration of any behavioral harassment. Given the small size
of calculated Level A harassment zones--maximum of 13 m for DTH in year
1, and 20 m for the worst-case scenario of impact-driven 36-in steel
piles with a bubble curtain--we do not anticipate any potential for
Level A harassment of killer whales.
Dall's Porpoise--We assume rare and infrequent occurrence of Dall's
porpoise at all installations. If observed, they typically occur in
groups of five (Smultea et al., 2017). Therefore, we assume that a
group of Dall's porpoise may occur in the vicinity of an installation
for a total of two days. We do not expect that this would happen
multiple times, and cannot predict where such an occurrence may happen,
so conservatively propose to authorize take by Level B harassment of a
total of 10 Dall's porpoise each project year.
The Navy plans to implement shutdown of pile driving activity at
any time if a Dall's porpoise is observed in the Level A harassment
zone. The calculated Level A harassment zone is as large as 445 m for
DTH of 24-in concrete in year 1 and as large as 646 m for impact
driving of 36-in steel piles with a bubble curtain in year 2. Take by
level A harassment would require that a porpoise be present at that
range for the full duration of 1,000 pile strikes. Given the rarity of
Dall's porpoise in the area, the Navy's commitment to shut down upon
observation of a porpoise within the Level A harassment zone, and the
likelihood that a porpoise would engage in aversive behavior prior to
experiencing PTS, we do not expect that any porpoise would be present
within a Level A harassment zone for sufficient duration to actually
experience PTS.
Harbor Porpoise--Level B exposure estimates for harbor porpoise
were calculated for each installation each year using the appropriate
density given in table 10, the largest appropriate ZOI for each pile
type, and the appropriate number of construction days.
<bullet> NBK Bangor: Pile driving is not planned at this
installation in year 1. For year 2, using the Hood Canal sub-region
density, 36 days of pile driving in year 2, and the largest ZOIs
calculated for each pile type at this location (31 km\2\ for vibratory
installation of 36-in steel piles) produces an estimate of 905
incidents of Level B harassment for harbor porpoise.
<bullet> NBK Bremerton: In year 1, using the Sinclair Inlet sub-
region density, 31 days of pile driving, and the largest ZOI calculated
for each pile type at this location (16 km\2\ for removal and
installation of 13-in timber piles, 0.2 km for impact installation of
24-in concrete piles, and 0.07 km for impact installation of 18-in
concrete) produces an estimate of 93 incidents of Level B harassment
for harbor porpoise. In year 2, using the Sinclair Inlet sub-region
density, 24 days of pile driving, and the largest ZOI calculated for
each pile type at this location (16 km\2\ for vibratory removal and
installation of 24-in steel piles) produces an estimate of 204
incidents of Level B harassment for harbor porpoise.
<bullet> NBK Manchester: In year 1, using the Vashon sub-region
density, 37 days of pile driving, and the largest ZOI calculated for
each pile type at this location (75.8 km\2\ for DTH of 24-in concrete
piles) produces an estimate of 701 incidents of Level B harassment for
harbor porpoise. There are no pile driving activities planned at this
installation in year 2.
<bullet> NS Everett: There are no pile driving activities planned
at this installation in year 1. In year 2, using the East Whidbey sub-
region density, 8 days of pile driving, and the largest ZOI calculated
each pile type at this location (8 km\2\) produces an estimate of 24
incidents of Level B harassment for harbor porpoise.
The Navy plans to implement shutdown of pile driving activity at
any time if a harbor porpoise is observed in the Level A harassment
zone. As a result of this proposed mitigation, we do not believe that
Level A harassment is a likely outcome. There are two instances where
the Level A harassment zone may extend beyond a distance where harbor
porpoise may reliably be detected by PSOs. In Year 1, the Level A
harassment zone is 445 m during DTH drilling of 24-in concrete at NBK
Manchester. In Year 2, the Level A harassment zone is 645 m during
impact driving of 36-in steel piles with a bubble curtain at NBK
Bangor. However, Rone et al. (2024) reported a notable absence of
harbor porpoise within 21 km\2\ in front of NBK Bangor. In both cases,
harbor porpoise are uncommon in the area. Given the Navy's commitment
to shut down upon observation of a porpoise within the Level A
harassment zone, and the likelihood that a porpoise would engage in
aversive behavior prior to experiencing PTS, we do not expect that any
porpoise would be present within a Level A harassment zone for
sufficient duration to actually experience PTS.
Across all installations, we propose to authorize 794 takes by
Level B harassment of harbor porpoise in year 1 and 1,157 takes by
Level B harassment of harbor porpoise in year 2.
Steller Sea Lion--Level B harassment estimates for Steller sea
lions were calculated for each installation using the appropriate
density given in table 10 or
[[Page 25600]]
site-specific abundance, the largest appropriate ZOI for each pile type
at each installation, and the appropriate number of days. Please see
Marine Mammal Monitoring Report at Navy Region Northwest Installations:
2008-2022 (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>) for
details of site-specific abundance information (Navy, 2023).
<bullet> NBK Bangor: Steller sea lions are routinely seen hauled
out from mid-September through May, with a maximum daily haul-out count
of 21 individuals in November (based on data collected between 2008 and
2022). Because the mean of monthly average counts per surveys between
2008-2022 was 1, we relied the average of the maximum count of hauled
out Steller sea lions for each month in the in-water work window (July-
January). The average of the monthly maximum counts during the in-water
work window provides an estimate of 7.25 sea lions present per day.
Using this value for 36 days in year 2 results in an estimate of 261
incidents of Level B harassment in year 2. There are no pile driving
activities planned at this installation in year 1.
<bullet> NBK Bremerton: Steller sea lions have been documented only
twice at this installation between 2008 and 2022. As such density
values were used to estimate take at this location. Using the Puget
Sound density value for fall-winter, 31 days of pile driving in year 1,
and the largest ZOI calculated for each pile type at this location (16
km\2\ for removal and installation of 13-in timber piles, 0.2 km for
impact installation of 24-in concrete piles, and 0.07 km for impact
installation of 18-in concrete) produces an estimate of 9 incidents of
Level B harassment for Steller sea lion in year 1. Using the Puget
Sound density value for fall-winter, 24 days of pile driving in year 2,
and the largest ZOI calculated for each pile type at this location (16
km\2\ for vibratory removal and installation of 24-in steel piles)
produces an estimate of 18 incidents of Level B harassment for Steller
sea lion in year 2.
<bullet> NBK Manchester: Steller sea lions are observed
periodically at NBK Manchester since surveys began in 2012. We estimate
take based on the monthly mean counts per surveys conducted from July
to February, between 2012 and 2022, which provides an estimate of six
Steller sea lions per day. In year 1, using this value for 37 days in
results in an estimate of 222 incidents of Level B harassment. There
are no pile driving activities planned at this installation in year 2.
<bullet> NS Everett: Steller sea lions were rarely observed at NS
Everett between 2012 and 2022. All observations were of lone
individuals hauled out on a PSB or in a nearby basin. We conservatively
estimate that one Steller sea lion could occur within the project area
per day. Using this value for 8 days in year 2 results in an estimate
of 8 incidents of Level B harassment in year 2. There are no pile
driving activities planned at this installation in year 1.
Given the small size of calculated Level A harassment zones--
maximum of 15 m for the worst-case scenario of DTH-installed 24-in
concrete piles in year 1 and maximum of 21 m for the worst-case
scenario of impact-driven 36-in steel piles with the use of a bubble
curtain in year 2--we do not anticipate any potential for Level A
harassment of Steller sea lions.
Across all installations we propose to authorize take by 231 takes
by Level B harassment of Steller sea lion in year 1 and 287 takes by
Level B harassment of Steller sea lions in year 2.
California Sea Lion--Level B harassment estimates for California
sea lions were calculated for each installation using the appropriate
site-specific abundance, the largest appropriate ZOI for each pile type
at each installation, and the appropriate number of days. Please see
Marine Mammal Monitoring Report at Navy Region Northwest Installations:
2008-2022 (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>) for
details of site-specific abundance information (Navy, 2023).
<bullet> NBK Bangor: California sea lions haul out in all months on
floating PSB and on submarines docked at Delta Pier, with lower numbers
in June through July. We estimate take based on the monthly mean counts
per surveys conducted from July to January, between 2012 and 2022,
which provides an estimate of 25 California sea lions per day. In year
2, using this value for 36 days results in an estimate of 900 incidents
of Level B harassment in year 2. There are no pile driving activities
planned at this installation in year 1.
<bullet> NBK Bremerton: California sea lions are routinely seen
hauled out on floats at NBK Bremerton during most of the year. We
estimate take based on the monthly mean count per surveys conducted
from July through February, between 2010 and 2022, which provides an
estimate of 98 California sea lions per day. In year 1, using this
value for 31 days generates an estimate of 3,038 incidents of Level B
harassment. In year 2, using this value for 24 days generates an
estimate of 2,352 incidents of Level B harassment in year 2.
<bullet> NBK Manchester: California sea lions have been observed at
this installation at least once each month of the year, with peak
numbers occurring in October and November. Floats used as haulouts are
periodically installed and removed, making numbers in the vicinity
highly variable. We estimate take based on the monthly mean count per
surveys conducted from July through February, between 2012 and 2022,
which provides an estimate of 24 California sea lions per day. In year
1, using this value for 37 days generates an estimate of 1,274
incidents of Level B harassment. There are no pile driving activities
planned at this installation in year 2.
<bullet> NS Everett: California sea lions have been observed every
month of the year. We estimate take based on the monthly mean count per
survey conducted from July through February between 2012 and 2022,
which provides an estimate of 48 California sea lions per day. In year
2, using this value for 8 days in year 2 generates an estimate of 384
incidents of Level B exposures. There are no pile driving activities
planned at this installation in year 1.
Given the small size of calculated Level A harassment zones--
maximum of 15 m for the worst-case scenario of DTH-installed 24-in
concrete piles in year 1 and maximum of 21 m for the worst-case
scenario of impact-driven 36-in steel piles with the use of a bubble
curtain in year 2--we do not anticipate any potential for Level A
harassment of California sea lions.
Across all installations we propose to authorize 3,926 takes by
Level B harassment of California sea lions in year 1 and 3,636 takes by
Level B harassment of California sea lions in year 2.
Harbor Seal--Harbor seals are expected to occur year-round at all
installations, with the greatest numbers expected at installations with
nearby haul-out sites. Level B exposure estimates for harbor seals were
calculated for each installation using the appropriate site-specific
abundance, the largest appropriate ZOI for each pile type at each
installation, and the appropriate number of days. Please see Marine
Mammal Monitoring Report at Navy Region Northwest Installations: 2008-
2022 (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>) for details of
site-specific abundance information (Navy, 2023).
[[Page 25601]]
Harbor seals are expected to be the most abundant marine mammal at
all installations, often occurring in and around existing in-water
structures in a way that may restrict observers' ability to adequately
observe seals and subsequently implement shutdowns. In addition, the
calculated Level A harassment zones are significantly larger than those
for sea lions, which may also be abundant at various installations at
certain times of year. For harbor seals in year 1, the largest
calculated Level A harassment zone is 200 m (compared with a maximum
zone of 15 m for sea lions), calculated for the worst-case scenario of
DTH-installed 24-in concrete piles (other scenarios range from 5-75 m).
In year 2, the largest calculated Level A harassment zone is 290 m
(compared with a maximum zone of 21 m for sea lions), calculated for
the worst-case scenario of impact-driven 36-in steel piles with the use
of a bubble curtain (other scenarios range from 1-21 m). Therefore, we
assume that some Level A harassment is likely to occur for harbor seals
and provide installation-specific estimates below.
<bullet> NBK Bangor: Harbor seals are year-round residents at NBK
Bangor and have been identified at least once during each calendar
month over several survey years. They have been observed swimming and
hauled out on man-made structures including docks, catwalks under the
dock at Marginal Pier, PSBs, and boats along the NBK Bangor waterfront,
The Navy plans to place fencing around the catwalks at Marginal Pier,
which may reduce harbor seal haulout opportunities at NBK Bangor.
Because the mean of monthly average counts per surveys between 2008-
2022 was <1, we estimate take by Level B harassment based on the mean
maximum count per month of surveys conducted from July to January,
between 2008 and 2022, which provides an estimate of 16 harbor seals
per day. In year 2, using this value for 36 days results in an estimate
of 576 incidents of Level B exposures. There are no pile driving
activities planned at this installation in year 1.
The Level A harassment zone expected to occur during impact
installation of 36-in steel at NBK Bangor is 290 m. Since the Navy
plans to maintain a shutdown zone of at 180 m (see table 13), the Navy
estimates and NMFS agrees that one seal per day (n = 20) could remain
within the calculated Level A harassment zone for a sufficient period
to accumulate enough energy to result in PTS. As such, we propose to
authorize 20 incidents of take by Level A harassment.
<bullet> NBK Bremerton: Observations of harbor seals are
intermittent at NBK Bremerton. They are primarily observed swimming in
the water around piers and structures and less frequently hauled out on
floats and docked submarines. Because the mean of monthly average
counts per surveys between 2008-2022 was <1, we estimate take based on
the mean maximum count per month of surveys from July to February,
between 2010 and 2022, which provides an estimate of two harbor seals
per day. In year 1, using this value for 31 days results in an estimate
of 62 incidents of Level B exposures. In year 2, using this value for
24 days results in an estimate of 48 incidents of Level B harassment.
In year 1, the Level A harassment zone expected to occur during
impact installation of 18-in steel at NBK Bremerton is 39 m and the
Level A harassment zone expected to occur during impact installation of
24-in steel is 73 m. Although the Navy plans to shut down at distances
slightly larger than these Level A harassment zones (see table 12), the
Navy assumes and NMFS agrees that it is possible that one seal per day
could go unobserved and remain within the calculated zone for a
sufficient period to accumulate enough energy to result in PTS. As
such, we propose to authorize 20 takes by Level A harassment. In year
2, the largest Level A harassment zone is much smaller (<10 m) and as
such we do not expect take by Level A harassment to occur and we do not
propose to authorize such take.
<bullet> NBK Manchester: No harbor seal haulouts have been
identified at NBK Manchester, but seals regularly haul out at Orchard
Rocks and are observed swimming through the project area. We estimate
take based on the monthly mean count per survey conducted from July
through February between 2020 and 2022 (Orchard Rocks was incorporated
into surveys in 2020), which provides an estimate of 10 harbor seals
per day. In year 1, using this value for 37 days results in an estimate
of 370 incidents of Level B harassment. There are no pile driving
activities planned at this installation in year 2.
The Level A harassment zone expected to occur during DTH
installation of 24-in concrete at NBK Manchester is 200 m. Since the
Navy plans to shut down at 150 m due to practicability concerns (see
table 12), the Navy assumes and NMFS agrees that one seal per day (n =
37) could remain within the calculated zone for a sufficient period to
accumulate enough energy to result in PTS. As such, we propose to
authorize 37 incidents of take by Level A harassment.
<bullet> NS Everett: Harbor seals haul out year round on floats,
riprap, and human structures at NS Everett. We estimate take based on
the monthly mean count per survey conducted from July through February
between 2019 and 2022 (the east side of East Waterway was incorporated
into surveys in 2019), which provides an estimate of 266 harbor seals
per day. In year 2, using this value for 8 days results in an estimate
of 2,128 incidents of Level B harassment. There are no planned pile
driving activities at this installation in year 1.
The largest Level A harassment zone expected to occur at NS Everett
is 21 m and the Navy plans to shut down at this distance should a
harbor seal be observed entering or within this zone. As such we do not
expect take by Level A harassment to occur and we do not propose to
authorize such take here.
Any individuals exposed to the higher levels associated with the
potential for PTS closer to the source might also be behaviorally
disturbed, however, for the purposes of quantifying take we do not
count those exposures of one individual as both a Level A harassment
take and a Level B harassment take, and therefore takes by Level B
harassment calculated as described above are further modified to deduct
the proposed amount of take by Level A harassment. Therefore, in year
1, across all installations, NMFS proposes to authorize 57 takes by
Level A harassment and 432 takes by Level B harassment for harbor seal,
for a total of 489 takes. In year 2, across all installations, NMFS
proposes to authorize 20 takes by Level A harassment and 2,752 takes by
Level B harassment for harbor seal, for a total of 2,772 takes.
Northern Elephant Seal--Northern elephant seals are considered rare
visitors to Puget Sound. However, solitary juvenile elephant seals have
been known to sporadically haul out to molt in Puget Sound during
spring and summer months. Because there are occasional sightings in
Puget Sound, the Navy reasons that exposure of up to one seal to noise
above Level B harassment thresholds could occur for a two-day duration
for a total of 2 takes by Level B harassment of northern elephant seals
each year.
The total proposed take authorization for all species each year is
summarized in table 11 below. No authorization of take by Level A
harassment is proposed for authorization except a total of 57 such
incidents for harbor seals in year 1 and 20 such incidents for harbor
seals in year 2.
[[Page 25602]]
Table 11--Proposed Take Authorization by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1 Year 2
-------------------------------------------------------------------------------------------
Species Stock Proposed take as Proposed take as
Level A Level B a percentage of Level A Level B a percentage of
harassment harassment stock abundance harassment harassment stock abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback Whale...................... CenAmer./S Mex-CA-OR- 0 0 0 0 0 0
WA.
Mex-CA-OR-WA.......... 1 <1 0 1 <1
Hawai'i............... 3 <1 0 3 <1
Minke Whale......................... CA-OR-WA.............. 0 4 <1 0 4 <1
Gray Whale.......................... Eastern N Pacific..... 0 4 <1 0 4 <1
Killer Whale........................ W Coast Transient..... 0 12 3 0 12 3
E.N.P.--S Resident.... 0 20 27 0 20 27
Harbor Porpoise..................... WA. Inland............ 0 794 7 0 1,157 10
Dall's Porpoise..................... CA-OR-WA.............. 0 10 <1 0 10 <1
Steller Sea Lion.................... Eastern US............ 0 231 <1 0 287 <1
California Sea Lion................. US.................... 0 3,926 2 0 3,636 1.4
Northern Elephant Seal.............. CA Breeding........... 0 2 <1 0 2 <1
Harbor Seal......................... WA N Inland........... 57 375 4 0 2176 13
Hood Canal............ 0 0 0 20 576 17
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Timing--As described previously, the Navy would adhere to in-water
work windows designed for the protection of fish. These timing windows
would also benefit marine mammals by limiting the annual duration of
construction activities. At NBK Bangor, the Navy would adhere to a July
16 through January 15 window, while at the remaining facilities this
window is extended to February 15 each project year.
On a daily basis, in-water construction activities would occur only
during daylight hours (sunrise to sunset) except from July 16 to
September 15, when impact pile driving would only occur starting 2
hours after sunrise and ending 2 hours before sunset in order to
protect marbled murrelets (Brachyramphus marmoratus) during the nesting
season. The exception is NBK Bremerton, where marbled murrelets do not
occur.
Shutdown Zone--For all pile driving, removal, and DTH drilling, the
Navy would implement shutdowns within designated zones. The purpose of
a shutdown zone is generally to define an area within which shutdown of
activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). For all pile
driving activities, the Navy would establish a minimum shutdown zone
with a radial distance of 10 m. This minimum zone is intended to
prevent the already unlikely possibility of physical interaction with
construction equipment and to establish a precautionary minimum zone
with regard to acoustic effects. In most circumstances where the
predicted Level A harassment zone exceeds the minimum zone, the Navy
proposes to implement a shutdown zone greater or equal to the predicted
Level A harassment zone (see tables 12 and 13). However, in cases where
it would be challenging to detect marine mammals at the Level A
harassment isopleth and frequent shutdowns would create practicability
concerns (e.g., for phocids during DTH at NBK Manchester in year 1 and
impact pile driving at NBK Bangor in year 2), smaller shutdown zones
have been proposed. In addition, the Navy proposes to implement
shutdown upon observation of any large whales and killer whales within
a calculated Level B harassment zone. Recognizing that the entirety of
the Level B harassment zone cannot practicably be monitored, the Orca
Network would be consulted prior to commencing pile driving each day,
and pile driving would also be delayed or shutdown if low-frequency or
mid-frequency cetaceans are reported near or approaching the Level B
harassment zone. In all cases, predicted injury zones are calculated on
the basis of cumulative sound exposure, as peak pressure source levels
produce smaller predicted zones.
Finally, construction activities would be halted upon observation
of a species for which incidental take is not authorized or a species
for which incidental take has been authorized but the authorized number
of takes has been met entering or within the harassment zone.
[[Page 25603]]
Table 12--Shutdown Zones, Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (m) Level B Level B
Activity Pile size/type ----------------------------------------------------------------- harassment monitoring
LF MF HF PW OW zone (m) zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation................. 18-in Concrete......... 100 50 100 40 10 46 N/A
24-in Concrete......... 170 90 170 75 10 86 N/A
Vibratory Installation or Removal... 13-in Timber........... \2\ 5,412 \2\ 5,412 15 10 10 5,412 \1\ 400
DTH................................. 24-in Concrete......... \2\ 13,594 \2\ 13,594 \3\ 450 150 20 13,594 \1\ 450
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers must be able to monitor at minimum the Level B monitoring zone prior to commencing vibratory pile driving and removal and DTH drilling.
\2\ This shutdown zone likely extends beyond the distance that low- and mid-frequency cetaceans can be reliably detected. Observers will monitor this
shutdown zone to the maximum extent possible based on the number and location of PSOs deployed and weather conditions.
\3\ This shutdown zone likely extends beyond the distance that harbor porpoise can be reliably detected. However, harbor porpoise are uncommon near NKB
Manchester, and it is likely that they would engage in aversive behavior prior to experiencing PTS. As such, we do not expect that any porpoise would
be present within a Level A harassment zone for sufficient duration to actually experience PTS.
Table 13--Shutdown Zones, Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (m) Level B Level B
Activity Pile size/type ----------------------------------------------------------------- harassment monitoring
LF MF HF PW OW zone (m) zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation................. 12-in Steel............ 50 50 50 30 10 39.8 N/A
36-in Steel............ 650 650 \3\ 650 180 25 541.2 N/A
Vibratory Installation or Removal... 12-in Steel............ 1,585 1,585 10 10 10 1,585 \1\ 400
24-in Steel............ \2\ 5,412 \2\ 5,412 15 10 10 5,412 \1\ 400
36-in Steel............ \2\ 11,659 \2\ 11,659 40 20 10 11,659 \1\ 400
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers must be able to monitor at minimum the Level B monitoring zone prior to commencing vibratory pile driving and removal
\2\ This shutdown zone likely extends beyond the distance that low- and mid-frequency cetaceans can be reliably detected. Observers will monitor this
shutdown zone to the maximum extent possible based on the number and location of deployed PSOs and weather conditions
\3\ This shutdown zone likely extends beyond the distance that harbor porpoise can be reliably detected. However, harbor porpoise were notably absent
within 21 km\2\ in front of NKB Bangor (Rone et al., 2024) and it is likely that they would engage in aversive behavior prior to experiencing PTS. As
such, we do not expect that any porpoise would be present within a Level A harassment zone for sufficient duration to actually experience PTS.
Protected Species Observers--The number and placement of PSOs
during all construction activities (described in the Proposed
Monitoring and Reporting section) would ensure that the entire shutdown
zone is visible, except in cases when the shutdown zone is based on the
Level B harassment zone (large whales and killer whales). In such
cases, PSOs must be able to monitor at minimum the Level A harassment
zone. The Navy would employ at least three PSOs for all pile driving
and DTH drilling.
Monitoring for Level B Harassment--PSOs would monitor the shutdown
zones and beyond to the extent that PSOs can see. Monitoring beyond the
shutdown zones enables observers to be aware of and communicate the
presence of marine mammals in the project areas outside the shutdown
zones and thus prepare for a potential cessation of activity should the
animal enter the shutdown zone. Additionally, prior to commencing pile
driving, PSOs will contact Navy marine biologists or the Orca Network
directly to obtain reports of large whales in the area.
In order to document observed incidents of harassment, PSOs record
all marine mammal observations, regardless of location. The PSO's
location and the location of the pile being driven are known, and the
location of the animal may be estimated as a distance from the observer
and then compared to the location from the pile. It may then be
estimated whether the animal was exposed to sound levels constituting
incidental harassment on the basis of predicted distances to relevant
thresholds in post-processing of observational data, and a precise
accounting of observed incidents of harassment created.
Pre and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs will observe the shutdown zone, Level A
harassment zone, and Level B harassment zone (to the extent possible
based on the number and location of PSOs and weather conditions) for a
period of 30 minutes. Pre-start clearance monitoring must be conducted
during periods of visibility sufficient for the lead PSO to determine
that the shutdown zones and, during vibratory driving and removal and
DTH drilling, the Level B monitoring zone, are clear of marine mammals,
If these zones are obscured by fog or poor lighting conditions, in-
water construction activity will not be initiated until the entire
shutdown zone is visible. Pile driving may commence following 30
minutes of observation when the determination is made that the shutdown
zones and, during vibratory driving and removal and DTH drilling, the
Level B monitoring zone, are clear of marine mammals. If a marine
mammal is observed entering or within these zones, pile driving
activity must be delayed or halted. During vibratory driving and
removal and DTH, the Navy will shut down upon any observation of large
whales and killer whales. If pile driving is delayed or halted due to
the presence of a marine mammal, the activity may not commence or
resume until either the animal has voluntarily exited and been visually
confirmed beyond the shutdown zone or 15 minutes have passed without
re-detection of the animal.
The Navy also plans to take measures to ensure that killer whales
and large cetaceans (i.e., humpback whale, gray whale, and minke whale)
are not located within the vicinity of the project area, including, but
not limited to, contacting and/or reviewing the latest sightings data
from the Orca Network and/or Center for Whale Research, including
passive acoustic detections, to determine the location of the nearest
marine mammal sightings.
Soft Start--The use of a soft start procedure is believed to
provide additional protection to marine mammals by warning marine
mammals or providing them with a chance to leave the area prior to the
hammer operating at full capacity. The Navy will utilize soft start
techniques for impact pile driving. We require an initial set of three
strikes from the impact hammer at reduced energy, followed by a 30-
second waiting period, then two subsequent three-strike sets. Soft
start
[[Page 25604]]
will be required at the beginning of each day's impact pile driving
work and at any time following a cessation of impact pile driving of 30
minutes or longer; the requirement to implement soft start for impact
driving is independent of whether vibratory driving has occurred within
the prior 30 minutes. Soft start is not required during vibratory pile
driving activities.
Bubble Curtain--A bubble curtain would be used for all impact
driving of steel piles to attenuate noise. A bubble curtain would be
employed during impact installation or proofing of steel pile where
water depths are greater than 2 ft (0.67 m). Bubble curtains are not
proposed for installation of other pile types due to the relatively low
source levels, as the requirement to deploy the curtain system at each
driven pile results in a significantly lower production rate. Where a
bubble curtain is used, the contractor would be required to turn it on
prior to the soft start in order to flush fish from the area closest to
the driven pile.
To avoid loss of attenuation from design and implementation errors,
the Navy will require specific bubble curtain design specifications,
including testing requirements for air pressure and flow at each
manifold ring prior to initial impact hammer use, and a requirement for
placement on the substrate. The bubble curtain must distribute air
bubbles around 100 percent of the piling perimeter for the full depth
of the water column. 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. The contractor shall also train personnel in the proper
balancing of air flow to the bubblers, and must 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 standards shall occur prior to use for impact
driving.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring--Marine mammal monitoring must be conducted in
accordance with the Marine Mammal Monitoring and Mitigation Plan.
Marine mammal monitoring during pile driving and removal and DTH
drilling must be conducted by NMFS-approved PSOs in a manner consistent
with the following:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor), and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> Other PSOs may substitute other relevant experience,
education (degree in biological science or related field) or training
for experience performing the duties of a PSO during construction
activities pursuant to a NMFS-issued incidental take authorization;
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator will be designated. The lead
observer will be required to have prior experience working as a marine
mammal observer during construction activity pursuant to a NMFS-issued
incidental take authorization; and
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to each IHA.
PSOs should also have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including, but not limited to, the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was note implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Visual monitoring will be conducted by a minimum of three trained
PSOs positioned at suitable vantage points practicable (e.g., from a
small boat, the pile driving barge, on shore, piers, or any other
suitable location). One PSO will have an unobstructed view of all water
within the shutdown zone, and during vibratory pile driving and removal
and DTH drilling, the Level B monitoring zone. Remaining PSOs will
observe as much as the Level A and Level B harassment zones as
possible.
[[Page 25605]]
Monitoring will be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
will record all incidents of marine mammal occurrence, regardless of
distance from activity, and will document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than 30 minutes.
Acoustic Monitoring
The Navy plans to conduct hydroacoustic monitoring for a subset of
impact-driven steel piles for projects including more than three piles
where a bubble curtain is used (relevant to year 2 project activities
only).
Reporting
The Navy will submit a draft marine mammal monitoring report to
NMFS within 90 days after the completion of pile driving activities, or
60 days prior to a requested date of issuance of any future IHAs for
the project, or other projects at the same location, whichever comes
first. The marine mammal monitoring report will include an overall
description of work completed, a narrative regarding marine mammal
sightings, and associated PSO data sheets. Specifically, the report
will include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (1) The number and type of piles that
were driven and the method (e.g., impact or vibratory); and (2) Total
duration of driving time for each pile (vibratory driving) and number
of strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: (1) Name of PSO who sighted the animal(s) and PSO location
and activity at time of sighting; (2) Time of sighting; (3)
Identification of the animal(s) (e.g., genus/species, lowest possible
taxonomic level, or unidentified), PSO confidence in identification,
and the composition of the group if there is a mix of species; (4)
Distance and location of each observed marine mammal relative to the
pile being driven for each sighting; (5) Estimated number of animals
(min/max/best estimate); (6) Estimated number of animals by cohort
(adults, juveniles, neonates, group composition, etc.); (7) Animal's
closest point of approach and estimated time spent within the
harassment zone; and (8) Description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling),
including an assessment of behavioral responses thought to have
resulted from the activity (e.g., no response or changes in behavioral
state such as ceasing feeding, changing direction, flushing, or
breaching);
<bullet> Number of marine mammals detected within the harassment
zones, by species; and
<bullet> Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specific
actions that ensued, and resulting changes in behavior of the
animal(s), if any.
A final report must be prepared and submitted within 30 calendar
days following receipt of any NMFS comments on the draft report. If no
comments are received from NMFS within 30 calendar days of receipt of
the draft report, the report will be considered final. All PSO data
would be submitted electronically in a format that can be queried such
as a spreadsheet or database and would be submitted with the draft
marine mammal report.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the Holder must report the
incident to the Office of Protected Resources (OPR), NMFS
(<a href="/cdn-cgi/l/email-protection#1d4d4f3354494d335072737469726f74737a4f786d726f696e5d73727c7c337a726b"><span class="__cf_email__" data-cfemail="f7a7a5d9bea3a7d9ba98999e8398859e9990a5928798858384b799989696d9909881">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="eb829f9bc58d878e8682858cab85848a8ac58c849d">[email protected]</a>) and the
West Coast Regional Stranding Coordinator as soon as feasible. If the
death or injury was clearly caused by the specified activity, the
Holder must immediately cease the activities until NMFS OPR is able to
review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the IHAs. The Holder must not resume their activities until notified
by NMFS. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338;
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the majority of our analysis applies to all
the species listed in table 3, given that many of the anticipated
effects of this project on different marine mammal stocks are expected
to be relatively similar in nature. Where there are meaningful
differences between species or stocks, or groups of species, in
anticipated individual responses to activities, impact of expected take
on the population due to differences in population status, or impacts
on habitat, they are described independently in the analysis below.
[[Page 25606]]
Pile driving activities associated with the maintenance projects,
as described previously, have the potential to disturb or displace
marine mammals. Specifically, the specified activities may result in
take, in the form of Level B harassment (behavioral disturbance) only
(for all species other than harbor seal) from underwater sounds
generated from pile driving. Potential takes could occur if individual
marine mammals are present in the ensonified zone when pile driving is
happening.
No serious injury or mortality would be expected even in the
absence of the proposed mitigation measures. For all species other than
the harbor seal, no Level A harassment is anti
[…truncated; see source link]Indexed from Federal Register on April 11, 2024.
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