[Federal Register Volume 80, Number 77 (Wednesday, April 22, 2015)]
[Notices]
[Pages 22477-22501]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-09253]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XD857
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Wharf Maintenance Project
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for
authorization to take marine mammals incidental to construction
activities as part of a wharf maintenance project. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an incidental harassment authorization (IHA) to the
Navy to incidentally take marine mammals, by Level B Harassment only,
during the specified activity.
DATES: Comments and information must be received no later than May 22,
2015.
ADDRESSES: Comments on the application should be addressed to Jolie
Harrison, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service. Physical comments should
be sent to 1315 East-West Highway, Silver Spring, MD 20910 and
electronic comments should be sent to [email protected].
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. Comments received electronically,
including all attachments, must not exceed a 25-megabyte file size.
Attachments to electronic comments will be accepted in Microsoft Word
or Excel or Adobe PDF file formats only. All comments received are a
part of the public record and will generally be posted for public
viewing on the Internet at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without change. All personal identifying
[[Page 22478]]
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible.
FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
An electronic copy of the Navy's application and supporting
documents, as well as a list of the references cited in this document,
may be obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing
these documents, please call the contact listed above (see FOR FURTHER
INFORMATION CONTACT).
National Environmental Policy Act (NEPA)
The Navy prepared an Environmental Assessment (EA) to consider the
direct, indirect and cumulative effects to the human environment
resulting from the wharf maintenance project. NMFS has reviewed the EA
and believes it appropriate to adopt the EA in order to assess the
impacts to the human environment of issuance of an IHA to the Navy and
subsequently sign our own Finding of No Significant Impact (FONSI).
Information in the Navy's application, the Navy's EA, and this notice
collectively provide the environmental information related to proposed
issuance of this IHA for public review and comment. All documents are
available at the aforementioned Web site. We will review all comments
submitted in response to this notice as we complete the NEPA process,
including a final decision of whether to adopt the Navy's EA and sign a
FONSI, prior to a final decision on the incidental take authorization
request.
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified area, the incidental, but not intentional,
taking of small numbers of marine mammals, providing that certain
findings are made and the necessary prescriptions are established.
The incidental taking of small numbers of marine mammals may be
allowed only if NMFS (through authority delegated by the Secretary)
finds that the total taking by the specified activity during the
specified time period will (i) have a negligible impact on the species
or stock(s) and (ii) not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant). Further, the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such taking
must be set forth.
The allowance of such incidental taking under section 101(a)(5)(A),
by harassment, serious injury, death, or a combination thereof,
requires that regulations be established. Subsequently, a Letter of
Authorization may be issued pursuant to the prescriptions established
in such regulations, providing that the level of taking will be
consistent with the findings made for the total taking allowable under
the specific regulations. Under section 101(a)(5)(D), NMFS may
authorize such incidental taking by harassment only, for periods of not
more than one year, pursuant to requirements and conditions contained
within an IHA. The establishment of these prescriptions requires notice
and opportunity for public comment.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . .
an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.'' 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].''
Summary of Request
On November 4, 2014, we received a request from the Navy for
authorization to take marine mammals incidental to pile driving and
removal associated with maintenance of an explosives handling wharf
(EHW-1) in the Hood Canal at Naval Base Kitsap in Bangor, WA (NBKB).
The Navy submitted revised versions of the request on February 27 and
March 17, 2015. The latter of these was deemed adequate and complete.
The Navy proposes to replace four structurally unsound piles, between
July 16, 2015, and January 15, 2016.
The use of both vibratory and impact pile driving is expected to
produce underwater sound at levels that have the potential to result in
behavioral harassment of marine mammals. Species with the expected
potential to be present during all or a portion of the in-water work
window include the Steller sea lion (Eumetopias jubatus monteriensis),
California sea lion (Zalophus californianus), harbor seal (Phoca
vitulina richardii), killer whale (transient only; Orcinus orca), and
harbor porpoise (Phocoena phocoena vomerina). These species may occur
year-round in the Hood Canal, with the exception of the Steller sea
lion, which is present only from fall to late spring (approximately
late September to early May), and the California sea lion, which is
only present from late summer to late spring (approximately late August
to early June).
This would be the third such IHA for similar work on the same
structure, if issued. The Navy previously received IHAs for a two-year
maintenance project at EHW-1 conducted in 2011-12 and 2012-13 (76 FR
30130 and 77 FR 43049). Additional IHAs were issued to the Navy in
recent years for marine construction projects on the NBKB waterfront,
including the construction of a second explosives handling wharf (EHW-
2) immediately adjacent to EHW-1. Three consecutive IHAs were issued
for that project, in 2012-13 (77 FR 42279), 2013-14 (78 FR 43148), and
2014-15 (79 FR 43429). Additional projects include the Test Pile
Project (TPP), conducted in 2011-12 in the proposed footprint of the
EHW-2 to collect geotechnical data and test methodology in advance of
the project (76 FR 38361) and a minor project to install a new mooring
for an existing research barge, conducted in 2013-14 (78 FR 43165). In-
water work associated with all projects was conducted only during the
approved in-water work window (July 16-February 15). Monitoring reports
for all of these projects are available on the Internet at
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm and provide
environmental information related to proposed issuance of this IHA for
public review and comment.
Description of the Specified Activity
Overview
NBKB provides berthing and support services to Navy submarines and
other fleet assets. The Navy proposes to complete necessary maintenance
at the EHW-1 facility at NBKB as part of ongoing maintenance conducted
as necessary to maintain the structural
[[Page 22479]]
integrity of the wharf and ensure its continued functionality to
support necessary operational requirements. The EHW-1 facility,
constructed in 1977, requires ongoing maintenance due to the
deterioration of the wharf's existing piling sub-structure. The
proposed action includes the replacement of four existing 24-in hollow
prestressed octagonal concrete piles with four new 30-in concrete
filled steel pipe piles. Existing piles will be removed using a
pneumatic hammer and a crane. Vibratory pile driving will be the
primary method used to install new piles, though an impact hammer may
be used if substrate conditions prevent the advancement of piles to the
required depth or to verify the load-bearing capacity. Sound
attenuation measures (i.e., bubble curtain) would be used during all
impact hammer operations.
Dates and Duration
The Navy's specified activity would occur only during July 16
through January 15, within the allowable season for in-water work at
NBKB. This window is established by the Washington Department of Fish
and Wildlife in coordination with NMFS and the U.S. Fish and Wildlife
Service (USFWS) to protect juvenile salmon. A maximum of eight pile
driving days would occur, but the eight days could occur on any day
during the window. Vibratory driving, as compared with impact driving
or pile removal via pneumatic chipping, is expected to occur on only
four total days.
Impact pile driving during the first half of the in-water work
window (July 16 to September 23) may only occur between two hours after
sunrise and two hours before sunset to protect breeding marbled
murrelets (Brachyramphus marmoratus; an Endangered Species Act [ESA]-
listed bird under the jurisdiction of USFWS). Vibratory driving during
the first half of the window, and all in-water work conducted between
September 23 and January 15, may occur during daylight hours (sunrise
to sunset). Other construction (not in-water) may occur between 7 a.m.
and 10 p.m., year-round. Therefore, in-water work is restricted to
daylight hours (at minimum) and there is at least a nine-hour break
during the 24-hour cycle from all construction activity.
Specific Geographic Region
NBKB is located on the Hood Canal approximately 32 km west of
Seattle, Washington (see Figures 2-1 through 2-3 in the Navy's
application). The Hood Canal is a long, narrow fjord-like basin of the
western Puget Sound. Throughout its 108-km length, the width of the
canal varies from 1.6-3.2 km and exhibits strong depth/elevation
gradients and irregular seafloor topography in many areas. Although no
official boundaries exist along the waterway, the northeastern section
extending from the mouth of the canal at Admiralty Inlet to the
southern tip of Toandos Peninsula is referred to as northern Hood
Canal. NBKB is located within this region. Please see Section 2 of the
Navy's application for detailed information about the specific
geographic region, including physical and oceanographic
characteristics.
Detailed Description of Activities
Maintenance of necessary facilities for handling of explosive
materials is part of the Navy's sea-based strategic deterrence mission,
and the Navy has determined that EHW-1 structural integrity is
compromised due to deterioration of the wharf's piling sub-structure.
The EHW-1 consists of two 30-m access trestles and a main pier deck
that measures approximately 215 m in length. The wharf is supported by
both 16-in and 24-in hollow octagonal pre-cast concrete piles.
Additionally, there are steel and timber fender piles on the outboard
and inboard edges of the wharf (see Figures 1-1 through 1-4 in the
Navy's application).
The Navy proposes to replace four structurally unsound 24-in hollow
prestressed octagonal concrete piles, as well as performing additional
repair and replacement work above water that would not be expected to
result in effects to marine mammals. The piles would be replaced with
four 30-in concrete filled steel piles. Piles to be removed would first
be scored by a diver using a small pneumatic hammer and then removed by
crane. Pile installation will utilize vibratory pile drivers to the
greatest extent possible, and the Navy anticipates that most piles will
be able to be vibratory driven to within several feet of the required
depth. Pile drivability is, to a large degree, a function of soil
conditions and the type of pile hammer. The soil conditions encountered
during geotechnical explorations at NBKB indicate existing conditions
generally consist of fill or sediment of very dense glacially
overridden soils, and recent experience at other construction locations
along the NBKB waterfront indicates that most piles should be able to
be driven with a vibratory hammer to proper embedment depth. However,
difficulties during pile driving may be encountered as a result of
obstructions, such as rocks or boulders, which may exist throughout the
project area. If difficult driving conditions occur, usage of an impact
hammer would occur. Impact driving may also be used to verify load-
bearing capacity, or proof, installed piles.
Description of Marine Mammals in the Area of the Specified Activity
There are eight marine mammal species with recorded occurrence in
the Hood Canal during the past fifteen years, including five cetaceans
and three pinnipeds. The harbor seal resides year-round in Hood Canal,
while the Steller sea lion and California sea lion inhabit Hood Canal
during portions of the year. Harbor porpoises may transit through the
project area and occur regularly in Hood Canal, while transient killer
whales could be present in the project area but do not have regular
occurrence in the Hood Canal. The Dall's porpoise (Phocoenoides dalli
dalli), humpback whale (Megaptera novaeangliae), and gray whale
(Eschrichtius robustus) have been observed in Hood Canal, but their
presence is sufficiently rare that we do not believe there is a
reasonable likelihood of their occurrence in the project area during
the proposed period of validity for this IHA. The latter three species
are not carried forward for further analysis beyond this section.
We have reviewed the Navy's detailed species descriptions,
including life history information, for accuracy and completeness and
refer the reader to Sections 3 and 4 of the Navy's application instead
of reprinting the information here. Please also refer to NMFS' Web site
(www.nmfs.noaa.gov/pr/species/mammals/) for generalized species
accounts and to the Navy's Marine Resource Assessment for the Pacific
Northwest, which documents and describes the marine resources that
occur in Navy operating areas of the Pacific Northwest, including Puget
Sound (DoN, 2006). The document is publicly available at:
www.navfac.navy.mil/products_and_services/ev/products_and_services/marine_resources/marine_resource_assessments.html (accessed March 25,
2015).
Table 1 lists the marine mammal species with expected potential for
occurrence in the vicinity of NBKB during the project timeframe and
summarizes key information regarding stock status and abundance.
Taxonomically, we follow Committee on Taxonomy (2014). Please see NMFS'
Stock Assessment Reports (SAR), available at www.nmfs.noaa.gov/pr/sars,
for more detailed accounts of these stocks' status and abundance. The
harbor seal, California sea lion and harbor porpoise are addressed in
the
[[Page 22480]]
Pacific SARs (e.g., Carretta et al., 2014, 2015), while the Steller sea
lion and transient killer whale are treated in the Alaska SARs (e.g.,
Allen and Angliss, 2014, 2015).
In the species accounts provided here, we offer a brief
introduction to the species and relevant stock as well as available
information regarding population trends and threats, and describe any
information regarding local occurrence.
Table 1--Marine Mammals Potentially Present in the Vicinity of NBKB
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Stock abundance (CV, Relative occurrence in
Species Stock ESA/ MMPA status; Nmin, most recent PBR \3\ Annual M/ Hood Canal; season of
strategic (Y/N) \1\ abundance survey) \2\ SI \4\ occurrence
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Delphinidae
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Killer whale....................... West coast transient -; N................. 243 (n/a; 2009)....... 2.4 0 Rare; year-round (but
\6\. last observed in
2005).
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Family Phocoenidae (porpoises)
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Harbor porpoise.................... Washington inland -; N................. 10,682 (0.38; 7,841; unk >=2.2 Possible regular
waters \7\. 2003). presence; year-round.
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Order Carnivora--Superfamily Pinnipedia
Family Otariidae (eared seals and sea lions)
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California sea lion................ U.S................... -; N................. 296,750 (n/a; 153,337; 9,200 389 Seasonal/common; Fall
2011). to late spring (Aug
to Jun).
Steller sea lion................... Eastern U.S.\5\....... -; N................. 60,131-74,448 (n/a; 1,645 \9\ 92.3 Seasonal/occasional;
36,551; 2008-13) \8\. Fall to late spring
(Sep to May).
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Family Phocidae (earless seals)
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Harbor seal........................ Hood Canal \7\........ -; N................. 3,555 (0.15; unk; unk 0.2 Common; Year-round
1999). resident.
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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 (see
footnote 3) 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\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For killer whales, the
abundance values represent direct counts of individually identifiable animals; therefore there is only a single abundance estimate with no associated
CV. For certain stocks of pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction
factor derived from knowledge of the species (or similar species) life history to arrive at a best abundance estimate; therefore, there is no
associated CV. In these cases, the minimum abundance may represent actual counts of all animals ashore.
\3\ Potential biological removal, 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 size (OSP).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value. All
values presented here are from the draft 2014 SARs (www.nmfs.noaa.gov/pr/sars/draft.htm).
\5\ Abundance estimates (and resulting PBR values) for these stocks are new values presented in the draft 2014 SARs. This information was made available
for public comment and is currently under review and therefore may be revised prior to finalizing the 2014 SARs. However, we consider this information
to be the best available for use in this document.
\6\ The abundance estimate for this stock includes only animals from the ``inner coast'' population occurring in inside waters of southeastern Alaska,
British Columbia, and Washington--excluding animals from the ``outer coast'' subpopulation, including animals from California--and therefore should be
considered a minimum count. For comparison, the previous abundance estimate for this stock, including counts of animals from California that are now
considered outdated, was 354.
\7\ Abundance estimates for these stocks are greater than eight years old and are therefore not considered current. PBR is considered undetermined for
these stocks, as there is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates,
as these represent the best available information for use in this document.
\8\ Best abundance is calculated as the product of pup counts and a factor based on the birth rate, sex and age structure, and growth rate of the
population. A range is presented because the extrapolation factor varies depending on the vital rate parameter resulting in the growth rate (i.e.,
high fecundity or low juvenile mortality).
\9\ PBR is calculated for the U.S. portion of the stock only (excluding animals in British Columbia) and assumes that the stock is not within its OSP.
If we assume that the stock is within its OSP, PBR for the U.S. portion increases to 2,193.
Although present in Washington inland waters in small numbers
(Falcone et al., 2005), primarily in the Strait of Juan de Fuca and San
Juan Islands but also occasionally in Puget Sound, the humpback whale
is not typically present in Hood Canal. Archived sighting records show
no confirmed observations from 2001-11 (www.orcanetwork.org; accessed
March 26, 2015), and no records are found in the literature. In
January-February of 2012, and again in 2015, one individual was
observed in Hood Canal repeatedly over a period of several weeks. No
other sightings have been recorded.
Gray whales generally migrate southbound past Washington in late
December and January, and transit past
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Washington on the northbound return in March to May. Gray whales do not
generally make use of Washington inland waters, but have been observed
in certain portions of those waters in all months of the year, with
most records occurring from March through June (Calambokidis et al.,
2010; www.orcanetwork.org) and associated with regular feeding areas.
Usually fewer than twenty gray whales visit the inner marine waters of
Washington and British Columbia beginning in about January, and six to
ten of these are individual whales that return most years to feeding
sites in northern Puget Sound. The remaining individuals occurring in
any given year generally appear unfamiliar with feeding areas, often
arrive emaciated, and commonly die of starvation (WDFW, 2012). Gray
whales have been sighted in Hood Canal on six occasions since 1999
(including a stranded whale), with the most recent report in November
2010 (www.orcanetwork.org).
In Washington, Dall's porpoises are most abundant in offshore
waters where they are year-round residents, although interannual
distribution is highly variable (Green et al., 1992). In inland waters,
Dall's porpoises are most frequently observed in the Strait of Juan de
Fuca and Haro Strait between San Juan Island and Vancouver Island
(Nysewander et al., 2005), but are seen occasionally in southern Puget
Sound and may also occasionally occur in Hood Canal. Only a single
Dall's porpoise has been observed at NBKB, in deeper water during a
2008 summer survey conducted by the Navy (Tannenbaum et al., 2009). On
the basis of this single observation, we previously assumed it
appropriate to authorize incidental take of this species. However,
there have been no subsequent observations of Dall's porpoises in Hood
Canal during either dedicated vessel line-transect surveys or project-
specific monitoring and we no longer believe that the species may be
reasonably expected to be present in the action area.
Steller Sea Lion
Steller sea lions are distributed mainly around the coasts to the
outer continental shelf along the North Pacific rim from northern
Hokkaido, Japan through the Kuril Islands and Okhotsk Sea, Aleutian
Islands and central Bering Sea, southern coast of Alaska and south to
California (Loughlin et al., 1984). Based on distribution, population
response, and phenotypic and genotypic data, two separate stocks of
Steller sea lions are recognized within U.S. waters, with the
population divided into western and eastern distinct population
segments (DPS) at 144[deg]W (Cape Suckling, Alaska) (Loughlin, 1997).
The eastern DPS extends from California to Alaska, including the Gulf
of Alaska, and is the only stock that may occur in the Hood Canal.
According to NMFS' recent status review (NMFS, 2013), the best
available information indicates that the overall abundance of eastern
DPS Steller sea lions has increased for a sustained period of at least
three decades while pup production has also increased significantly,
especially since the mid-1990s. Johnson and Gelatt (2012) provided an
analysis of growth trends of the entire eastern DPS from 1979-2010,
indicating that the stock increased during this period at an annual
rate of 4.2 percent (90% CI 3.7-4.6). Most of the overall increase
occurred in the northern portion of the range (southeast Alaska and
British Columbia), but pup counts in Oregon and California also
increased significantly (e.g., Merrick et al., 1992; Sease et al.,
2001; Olesiuk and Trites, 2003; Fritz et al. 2008; Olesiuk, 2008; NMFS,
2008, 2013). In Washington, Pitcher et al. (2007) reported that Steller
sea lions, presumably immature animals and non-breeding adults,
regularly used four haul-outs, including two ``major'' haul-outs (>50
animals). The same study reported that the numbers of sea lions counted
between 1989 and 2002 on Washington haul-outs increased significantly
(average annual rate of 9.2 percent) (Pitcher et al., 2007). Although
the stock size has increased, its status relative to OSP size is
unknown. However, the consistent long-term estimated annual rate of
increase may indicate that the stock is reaching OSP size (Allen and
Angliss, 2014).
The eastern stock breeds in rookeries located in southeast Alaska,
British Columbia, Oregon, and California. There are no known breeding
rookeries in Washington (Allen and Angliss, 2014) but eastern stock
Steller sea lions are present year-round along the outer coast of
Washington, including immature animals or non-breeding adults of both
sexes. In 2011, the minimum count for Steller sea lions in Washington
was 1,749 (Allen and Angliss, 2014), up from 516 in 2001 (Pitcher et
al., 2007). In Washington, Steller sea lions primarily occur at haul-
out sites along the outer coast from the Columbia River to Cape
Flattery and in inland waters sites along the Vancouver Island
coastline of the Strait of Juan de Fuca (Jeffries et al., 2000; Olesiuk
and Trites, 2003; Olesiuk, 2008). Numbers vary seasonally in Washington
waters with peak numbers present during the fall and winter months
(Jeffries et al., 2000). Beginning in 2008, Steller sea lions have been
observed at NBKB hauled out on submarines at Delta Pier (located
approximately 1.25 km south of the project site) during fall through
spring months, with September 26 as the earliest documented arrival.
When Steller sea lions are present, there are typically one to four
individuals, with a maximum observed group size of eleven.
Harbor Seal
Harbor seals inhabit coastal and estuarine waters and shoreline
areas of the northern hemisphere from temperate to polar regions. The
eastern North Pacific subspecies is found from Baja California north to
the Aleutian Islands and into the Bering Sea. Multiple lines of
evidence support the existence of geographic structure among harbor
seal populations from California to Alaska (e.g., O'Corry-Crowe et al.,
2003; Temte, 1986; Calambokidis et al., 1985; Kelly, 1981; Brown, 1988;
Lamont, 1996; Burg, 1996). Harbor seals are generally non-migratory,
and analysis of genetic information suggests that genetic differences
increase with geographic distance (Westlake and O'Corry-Crowe, 2002).
However, because stock boundaries are difficult to meaningfully draw
from a biological perspective, three separate harbor seal stocks have
been recognized for management purposes along the west coast of the
continental U.S.: (1) Inland waters of Washington (including Hood
Canal, Puget Sound, and the Strait of Juan de Fuca out to Cape
Flattery), (2) outer coast of Oregon and Washington, and (3) California
(Carretta et al., 2014). Multiple stocks are recognized in Alaska.
Samples from Washington, Oregon, and California demonstrate a high
level of genetic diversity and indicate that the harbor seals of
Washington inland waters possess unique haplotypes not found in seals
from the coasts of Washington, Oregon, and California (Lamont et al.,
1996).
Recent genetic evidence indicates that harbor seals of Washington
inland waters have sufficient population structure to warrant division
into multiple distinct stocks (Huber et al., 2010, 2012). Based on
studies of pupping phenology, mitochondrial DNA, and microsatellite
variation, Carretta et al. (2014) divide the Washington inland waters
stock into three new populations, and present these as stocks: (1)
Southern Puget Sound (south of the Tacoma Narrows Bridge); (2)
Washington northern inland waters (including Puget Sound north of the
Tacoma Narrows Bridge, the San
[[Page 22482]]
Juan Islands, and the Strait of Juan de Fuca); and (3) Hood Canal. Only
the Hood Canal stock of harbor seals is expected to occur in the action
area.
The best available abundance estimate was derived from aerial
surveys of harbor seals in Washington conducted during the pupping
season in 1999, during which time the total numbers of hauled-out seals
(including pups) were counted (711; Jeffries et al., 2003). Radio-
tagging studies conducted at six locations collected information on
harbor seal haul-out patterns in 1991-92, resulting in a pooled
correction factor (across three coastal and three inland sites) of 1.53
to account for animals in the water which are missed during the aerial
surveys (Huber et al., 2001), which, coupled with the aerial survey
counts, previously provided the abundance estimate. More recent tagging
information specifically conducted in Hood Canal suggests that harbor
seals in Hood Canal haul out twenty percent of the time (London et al.,
2012). Therefore, the aerial surveys represented only twenty percent of
the population, and the abundance estimate has been revised accordingly
(see Table 1).
Harbor seal counts in Washington State increased at an annual rate
of six percent from 1983-96, increasing to ten percent for the period
1991-96 (Jeffries et al., 1997). The population is thought to be
stable, and harbor seals in Washington inland waters have generally
been considered to be within OSP size (Jeffries et al., 2003).
Harbor seals are the most abundant marine mammal in Hood Canal,
where they can occur anywhere year-round and are considered resident,
and are the only pinniped that breeds in inland Washington waters
(Jeffries et al., 2003). They are year-round, non-migratory residents,
pup (i.e., give birth) in Hood Canal, and the population is considered
closed, meaning that they do not have much movement outside of Hood
Canal (London, 2006). Surveys in the Hood Canal from the mid-1970s to
2000 show a fairly stable population between 600-1,200 seals, and the
abundance of harbor seals in Hood Canal has likely stabilized at its
carrying capacity of approximately 1,000 seals (Jeffries et al., 2003).
Harbor seals have been consistently sighted during Navy surveys, found
in all marine habitats including nearshore waters and deeper water, and
have been observed hauled out on manmade objects such as buoys (Agness
and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011). Harbor seals were
commonly observed in the water during monitoring conducted for other
projects at NBKB in 2011-13 (HDR, 2012a, 2012b; Hart Crowser, 2013).
The project area is not known as a regular pupping or haul-out
site, as harbor seals in Hood Canal prefer river deltas and exposed
tidal areas (London, 2006). The closest haul-out to the project area is
approximately 16 km southwest of NBKB at Dosewallips River mouth,
outside the potential area of effect for this project (see Figure 4-1
of the Navy's application). However, recent observations have shown
that harbor seals frequently haul-out opportunistically along the NBKB
waterfront (though not on many of the larger structures, which are
inaccessible to harbor seals, or on docked submarines, which are
favored by sea lions) and that pupping does occur along the NBKB
waterfront. Pupping has been observed on the NBKB waterfront at
Carderock Pier and Service Pier (both locations over a mile south of
the project site), and a harbor seal neonate was observed on a small
floating dock near the project site in 2013. Evidence of pupping has
been observed in other locations, and Navy biologists now believe that
pupping may occur regularly at the Service Pier. During most of the
year, all age and sex classes (except neonates) occur in the project
area throughout the period of construction activity. Despite evidence
of pupping, harbor seal neonates would not generally be expected to be
present during pile driving.
California Sea Lion
California sea lions range from the Gulf of California north to the
Gulf of Alaska, with breeding areas located in the Gulf of California,
western Baja California, and southern California. Five genetically
distinct geographic populations have been identified: (1) Pacific
temperate, (2) Pacific subtropical, and (3-5) southern, central, and
northern Gulf of California (Schramm et al., 2009). Rookeries for the
Pacific temperate population are found within U.S. waters and just
south of the U.S.-Mexico border, and animals belonging to this
population may be found from the Gulf of Alaska to Mexican waters off
Baja California. For management purposes, a stock of California sea
lions comprising those animals at rookeries within the U.S. is defined
(i.e., the U.S. stock of California sea lions) (Carretta et al., 2014).
Pup production at the Coronado Islands rookery in Mexican waters is
considered an insignificant contribution to the overall size of the
Pacific temperate population (Lowry and Maravilla-Chavez, 2005).
Trends in pup counts from 1975 through 2008 have been assessed for
four rookeries in southern California and for haul-outs in central and
northern California. During this time period counts of pups increased
at an annual rate of 5.4 percent, excluding six El Ni[ntilde]o years
when pup production declined dramatically before quickly rebounding
(Carretta et al., 2014). The maximum population growth rate was 9.2
percent when pup counts from the El Ni[ntilde]o years were removed.
There are indications that the California sea lion may have reached or
is approaching carrying capacity, although more data are needed to
confirm that leveling in growth persists (Carretta et al., 2014).
Sea lion mortality has been linked to the algal-produced neurotoxin
domoic acid (Scholin et al., 2000). Future mortality may be expected to
occur, due to the sporadic occurrence of such harmful algal blooms.
There is currently an Unusual Mortality Event (UME) declaration in
effect for California sea lions. Beginning in January 2013, elevated
strandings of California sea lion pups have been observed in southern
California, with live sea lion strandings nearly three times higher
than the historical average. Findings to date indicate that a likely
contributor to the large number of stranded, malnourished pups was a
change in the availability of sea lion prey for nursing mothers,
especially sardines. The causes and mechanisms of this UME remain under
investigation (www.nmfs.noaa.gov/pr/health/mmume/californiasealions2013.htm; accessed March 28, 2015).
An estimated 3,000 to 5,000 California sea lions migrate northward
along the coast to central and northern California, Oregon, Washington,
and Vancouver Island during the non-breeding season from September to
May (Jeffries et al., 2000) and return south the following spring
(Mate, 1975; Bonnell et al., 1983). In past years, peak numbers of up
to 1,000 California sea lions occur in Puget Sound (including Hood
Canal) during this time period (Jeffries et al., 2000). Given the
overall population increase, it is likely that seasonal occurrence in
Puget Sound has also increased.
California sea lions are present in Hood Canal during much of the
year with the exception of mid-June through August, and occur regularly
at NBKB, as observed during Navy waterfront surveys conducted from
April 2008 through December 2013 (DoN, 2013). They are known to utilize
a diversity of man-made structures for hauling out (Riedman, 1990) and,
although there are no regular California sea lion haul-outs known
within the Hood Canal (Jeffries
[[Page 22483]]
et al., 2000), they are frequently observed hauled out at several
opportune areas at NBKB (e.g., submarines, floating security fence,
barges). All documented instances of California sea lions hauling out
at NBKB have been on submarines docked at Delta Pier, where a maximum
of 122 California sea lions have been observed at any one time (DoN,
2013), and on pontoons of the NBKB floating security fence.
Killer Whale
Killer whales are one of the most cosmopolitan marine mammals,
found in all oceans with no apparent restrictions on temperature or
depth, although they do occur at higher densities in colder, more
productive waters at high latitudes and are more common in nearshore
waters (Leatherwood and Dahlheim, 1978; Forney and Wade, 2006). Killer
whales are found throughout the North Pacific, including the entire
Alaska coast, in British Columbia and Washington inland waterways, and
along the outer coasts of Washington, Oregon, and California. On the
basis of differences in morphology, ecology, genetics, and behavior,
populations of killer whales have largely been classified as
``resident'', ``transient'', or ``offshore'' (e.g., Dahlheim et al.,
2008). Several studies have also provided evidence that these ecotypes
are genetically distinct, and that further genetic differentiation is
present between subpopulations of the resident and transient ecotypes
(e.g., Barrett-Lennard, 2000). The taxonomy of killer whales is
unresolved, with expert opinion generally following one of two lines:
Killer whales are either (1) a single highly variable species, with
locally differentiated ecotypes representing recently evolved and
relatively ephemeral forms not deserving species status, or (2)
multiple species, supported by the congruence of several lines of
evidence for the distinctness of sympatrically occurring forms (Krahn
et al., 2004). Resident and transient whales are currently considered
to be unnamed subspecies (Committee on Taxonomy, 2014).
The resident and transient populations have been divided further
into different subpopulations on the basis of genetic analyses,
distribution, and other factors. Recognized stocks in the North Pacific
include Alaska residents; northern residents; southern residents; Gulf
of Alaska, Aleutian Islands, and Bering Sea transients; and west coast
transients, along with a single offshore stock. See Allen and Angliss
(2014) for more detail about these stocks. West coast transient killer
whales, which occur from California through southeastern Alaska, are
the only type expected to potentially occur in the project area.
It is thought that the stock grew rapidly from the mid-1970s to
mid-1990s as a result of a combination of high birth rate, survival, as
well as greater immigration of animals into the nearshore study area
(DFO, 2009). The rapid growth of the population during this period
coincided with a dramatic increase in the abundance of the whales'
primary prey, harbor seals, in nearshore waters. Population growth
began slowing in the mid-1990s and has continued to slow in recent
years (DFO, 2009). Population trends and status of this stock relative
to its OSP level are currently unknown. Analyses in DFO (2009)
estimated a rate of increase of about six percent per year from 1975 to
2006, but this included recruitment of non-calf whales into the
population.
Transient occurrence in inland waters appears to peak during August
and September, which is the peak time for harbor seal pupping, weaning,
and post-weaning (Baird and Dill, 1995). The number of transient killer
whales in Washington waters at any one time is probably fewer than
twenty individuals (Wiles, 2004). In 2003 and 2005, small groups of
transient killer whales (eleven and six individuals, respectively) were
present in Hood Canal for significant periods of time (59 and 172 days,
respectively) between the months of January and July. While present,
the whales preyed on harbor seals in the subtidal zone of the nearshore
marine and inland marine deeper water habitats (London, 2006).
Harbor Porpoise
Harbor porpoises are found primarily in inshore and relatively
shallow coastal waters (< 100 m) from Point Barrow (Alaska) to Point
Conception (California). Various genetic analyses and investigation of
pollutant loads indicate a low mixing rate for harbor porpoises along
the west coast of North America and likely fine-scale geographic
structure along an almost continuous distribution from California to
Alaska (e.g., Calambokidis and Barlow, 1991; Osmek et al., 1994;
Chivers et al., 2002, 2007). However, stock boundaries are difficult to
draw because any rigid line is generally arbitrary from a biological
perspective. On the basis of genetic data and density discontinuities
identified from aerial surveys, eight stocks have been identified in
the eastern North Pacific, including northern Oregon/Washington coastal
and inland Washington stocks (Carretta et al., 2013a). The Washington
inland waters stock includes individuals found east of Cape Flattery
and is the only stock that may occur in the project area.
Although long-term harbor porpoise sightings in southern Puget
Sound declined from the 1940s through the 1990s, sightings and
strandings have increased in Puget Sound and northern Hood Canal in
recent years and harbor porpoise are now considered to regularly occur
year-round in these waters (Carretta et al., 2014). Reasons for the
apparent decline, as well as the apparent rebound, are unknown. Recent
observations may represent a return to historical conditions, when
harbor porpoises were considered one of the most common cetaceans in
Puget Sound (Scheffer and Slipp, 1948). The status of harbor porpoises
in Washington inland waters relative to OSP is not known (Carretta et
al., 2014).
In 2006, a UME was declared for harbor porpoises throughout Oregon
and Washington, and a total of 114 strandings were reported in 2006-07.
The cause of the UME has not been determined and several factors,
including contaminants, genetics, and environmental conditions, are
still being investigated (Carretta et al., 2014).
Prior to recent construction projects conducted by the Navy at
NBKB, harbor porpoises were considered to have only occasional
occurrence in the project area. A single harbor porpoise had been
sighted in deeper water at NBKB during 2010 field observations
(Tannenbaum et al., 2011). However, while implementing monitoring plans
for work conducted from July-October, 2011, the Navy recorded multiple
sightings of harbor porpoise in the deeper waters of the project area
(HDR, 2012). Following these sightings, the Navy conducted dedicated
line transect surveys, recording multiple additional sightings of
harbor porpoises, and have revised local density estimates accordingly.
Potential Effects of the Specified Activity on Marine Mammals
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals. This
discussion also includes reactions that we consider to rise to the
level of a take and those that we do not consider to rise to the level
of a take (for example, with acoustics, we may include a discussion of
studies that showed animals not reacting at all to sound or exhibiting
barely measurable avoidance). This section is intended as a background
of potential effects and does not consider either the
[[Page 22484]]
specific manner in which this activity will be carried out or the
mitigation that will be implemented, and how either of those will shape
the anticipated impacts from this specific activity. The ``Estimated
Take by Incidental Harassment'' section later in this document will
include a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The ``Negligible Impact
Analysis'' section will include the analysis of how this specific
activity will impact marine mammals and will consider the content of
this section, the ``Estimated Take by Incidental Harassment'' section,
the ``Proposed Mitigation'' section, and the ``Anticipated Effects on
Marine Mammal Habitat'' section to draw conclusions regarding the
likely impacts of this activity on the reproductive success or
survivorship of individuals and from that on the affected marine mammal
populations or stocks. In the following discussion, we provide general
background information on sound and marine mammal hearing before
considering potential effects to marine mammals from sound produced by
vibratory and impact pile driving.
Description of Sound Sources
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks of a sound wave; lower frequency sounds have
longer wavelengths than higher frequency sounds and attenuate
(decrease) more rapidly in shallower water. Amplitude is the height of
the sound pressure wave or the `loudness' of a sound and is typically
measured using the decibel (dB) scale. A dB is the ratio between a
measured pressure (with sound) and a reference pressure (sound at a
constant pressure, established by scientific standards). It is a
logarithmic unit that accounts for large variations in amplitude;
therefore, relatively small changes in dB ratings correspond to large
changes in sound pressure. When referring to sound pressure levels
(SPLs; the sound force per unit area), sound is referenced in the
context of underwater sound pressure to 1 microPascal ([mu]Pa). One
pascal is the pressure resulting from a force of one newton exerted
over an area of one square meter. The source level (SL) represents the
sound level at a distance of 1 m from the source (referenced to 1
[mu]Pa). The received level is the sound level at the listener's
position. Note that all underwater sound levels in this document are
referenced to a pressure of 1 [mu]Pa and all airborne sound levels in
this document are referenced to a pressure of 20 [mu]Pa.
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Rms is calculated by squaring all of the
sound amplitudes, averaging the squares, and then taking the square
root of the average (Urick, 1983). Rms accounts for both positive and
negative values; squaring the pressures makes all values positive so
that they may be accounted for in the summation of pressure levels
(Hastings and Popper, 2005). This measurement is often used in the
context of discussing behavioral effects, in part because behavioral
effects, which often result from auditory cues, may be better expressed
through averaged units than by peak pressures.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in all
directions away from the source (similar to ripples on the surface of a
pond), except in cases where the source is directional. The
compressions and decompressions associated with sound waves are
detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown sources. These sources may include physical (e.g.,
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
sound (e.g., vessels, dredging, aircraft, construction). A number of
sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient noise for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf noise becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total noise at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient noise levels, as can some fish and shrimp. The frequency band
for biological contributions is from approximately 12 Hz to over 100
kHz.
Anthropogenic: Sources of ambient noise related to human
activity include transportation (surface vessels and aircraft),
dredging and construction, oil and gas drilling and production, seismic
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise
typically dominates the total ambient noise for frequencies between 20
and 300 Hz. In general, the frequencies of anthropogenic sounds are
below 1 kHz and, if higher frequency sound levels are created, they
attenuate rapidly (Richardson et al., 1995). Sound from identifiable
anthropogenic sources other than the activity of interest (e.g., a
passing vessel) is sometimes termed background sound, as opposed to
ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Underwater ambient noise was measured at approximately 113 dB rms
between 50 Hz and 20 kHz during the recent TPP project, approximately
1.85 mi from the project area (Illingworth & Rodkin, 2012). In 2009,
the average broadband ambient underwater noise levels were measured at
114 dB between
[[Page 22485]]
100 Hz and 20 kHz (Slater, 2009). Peak spectral noise from industrial
activity was noted below the 300 Hz frequency, with maximum levels of
110 dB noted in the 125 Hz band. In the 300 Hz to 5 kHz range, average
levels ranged between 83 and 99 dB. Wind-driven wave noise dominated
the background noise environment at approximately 5 kHz and above, and
ambient noise levels flattened above 10 kHz. Known sound levels and
frequency ranges associated with anthropogenic sources similar to those
that would be used for this project are summarized in Table 2.
Details of the source types are described in the following text.
Table 2--Representative Sound Levels of Anthropogenic Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Frequency
Sound source range (Hz) Underwater sound level Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
Small vessels............................ 250-1,000 151 dB rms at 1 m........... Richardson et al., 1995.
Tug docking gravel barge................. 200-1,000 149 dB rms at 100 m......... Blackwell and Greene, 2002.
Vibratory driving of 72-in steel pipe 10-1,500 180 dB rms at 10 m.......... Reyff, 2007.
pile.
Impact driving of 36-in steel pipe pile.. 10-1,500 195 dB rms at 10 m.......... Laughlin, 2007.
Impact driving of 66-in cast-in-steel- 10-1,500 195 dB rms at 10 m.......... Reviewed in Hastings and Popper, 2005.
shell (CISS) pile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
In-water construction activities associated with the project would
include impact pile driving and vibratory pile driving. The sounds
produced by these activities fall into one of two general sound types:
pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al., (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and
occur either as isolated events or repeated in some succession. Pulsed
sounds are all characterized by a relatively rapid rise from ambient
pressure to a maximal pressure value followed by a rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Impact hammers operate by repeatedly dropping a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak SPLs may be
180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals,
and exposure to sound can have deleterious effects. To appropriately
assess these potential effects, it is necessary to understand the
frequency ranges marine mammals are able to hear. Current data indicate
that not all marine mammal species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008). To reflect this, Southall et al. (2007) recommended
that marine mammals be divided into functional hearing groups based on
measured or estimated hearing ranges on the basis of available
behavioral data, audiograms derived using auditory evoked potential
techniques, anatomical modeling, and other data. The lower and/or upper
frequencies for some of these functional hearing groups have been
modified from those designated by Southall et al. (2007). The
functional groups and the associated frequencies are indicated below
(note that these frequency ranges do not necessarily correspond to the
range of best hearing, which varies by species):
Low-frequency cetaceans (mysticetes): functional hearing
is estimated to occur between approximately 7 Hz and 30 kHz (extended
from 22 kHz; Watkins, 1986; Au et al., 2006; Lucifredi and Stein, 2007;
Ketten and Mountain, 2009; Tubelli et al., 2012);
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): functional hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; now considered to
include two members of the genus Lagenorhynchus on the basis of recent
echolocation data and genetic data [May-Collado and Agnarsson, 2006;
Kyhn et al. 2009, 2010; Tougaard et al. 2010]): functional hearing is
estimated to occur between approximately 200 Hz and 180 kHz; and
Pinnipeds in water: functional hearing is estimated to
occur between approximately 75 Hz to 100 kHz for Phocidae (true seals)
and between 100 Hz and 40 kHz for Otariidae (eared seals), with the
greatest sensitivity between approximately 700 Hz and 20 kHz. The
pinniped functional hearing group was modified from Southall et al.
(2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013).
[[Page 22486]]
There are five marine mammal species (two cetacean and three
pinniped [two otariid and one phocid] species) with expected potential
to co-occur with Navy construction activities. Please refer to Table 1.
Of the two cetacean species that may be present, the killer whale is
classified as a mid-frequency cetacean and the harbor porpoise is
classified as a high-frequency cetacean.
Acoustic Effects, Underwater
Potential Effects of Pile Driving Sound--The effects of sounds from
pile driving might result in one or more of the following: temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, and masking (Richardson et al., 1995;
Gordon et al., 2004; Nowacek et al., 2007; Southall et al., 2007). The
effects of pile driving on marine mammals are dependent on several
factors, including the size, type, and depth of the animal; the depth,
intensity, and duration of the pile driving sound; the depth of the
water column; the substrate of the habitat; the standoff distance
between the pile and the animal; and the sound propagation properties
of the environment. Impacts to marine mammals from pile driving
activities are expected to result primarily from acoustic pathways. As
such, the degree of effect is intrinsically related to the received
level and duration of the sound exposure, which are in turn influenced
by the distance between the animal and the source. The further away
from the source, the less intense the exposure should be. The substrate
and depth of the habitat affect the sound propagation properties of the
environment. Shallow environments are typically more structurally
complex, which leads to rapid sound attenuation. In addition,
substrates that are soft (e.g., sand) would absorb or attenuate the
sound more readily than hard substrates (e.g., rock) which may reflect
the acoustic wave. Soft porous substrates would also likely require
less time to drive the pile, and possibly less forceful equipment,
which would ultimately decrease the intensity of the acoustic source.
In the absence of mitigation, impacts to marine species would be
expected to result from physiological and behavioral responses to both
the type and strength of the acoustic signature (Viada et al., 2008).
The type and severity of behavioral impacts are more difficult to
define due to limited studies addressing the behavioral effects of
impulsive sounds on marine mammals. Potential effects from impulsive
sound sources can range in severity from effects such as behavioral
disturbance or tactile perception to physical discomfort, slight injury
of the internal organs and the auditory system, or mortality (Yelverton
et al., 1973).
Hearing Impairment and Other Physical Effects--Marine mammals
exposed to high intensity sound repeatedly or for prolonged periods can
experience hearing threshold shift (TS), which is the loss of hearing
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt
et al., 2000; Finneran et al., 2002, 2005). TS can be permanent (PTS),
in which case the loss of hearing sensitivity is not recoverable, or
temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Marine mammals depend on
acoustic cues for vital biological functions, (e.g., orientation,
communication, finding prey, avoiding predators); thus, TTS may result
in reduced fitness in survival and reproduction. However, this depends
on the frequency and duration of TTS, as well as the biological context
in which it occurs. TTS of limited duration, occurring in a frequency
range that does not coincide with that used for recognition of
important acoustic cues, would have little to no effect on an animal's
fitness. Repeated sound exposure that leads to TTS could cause PTS. PTS
constitutes injury, but TTS does not (Southall et al., 2007). The
following subsections discuss in somewhat more detail the possibilities
of TTS, PTS, and non-auditory physical effects.
Temporary Threshold Shift--TTS is the mildest form of hearing
impairment that can occur during exposure to a strong sound (Kryter,
1985). While experiencing TTS, the hearing threshold rises, and a sound
must be stronger in order to be heard. In terrestrial mammals, TTS can
last from minutes or hours to days (in cases of strong TTS). For sound
exposures at or somewhat above the TTS threshold, hearing sensitivity
in both terrestrial and marine mammals recovers rapidly after exposure
to the sound ends. Few data on sound levels and durations necessary to
elicit mild TTS have been obtained for marine mammals, and none of the
published data concern TTS elicited by exposure to multiple pulses of
sound. Available data on TTS in marine mammals are summarized in
Southall et al. (2007).
Given the available data, the received level of a single pulse
(with no frequency weighting) might need to be approximately 186 dB re
1 [mu]Pa\2\-s (i.e., 186 dB sound exposure level [SEL] or approximately
221-226 dB p-p [peak]) in order to produce brief, mild TTS. Exposure to
several strong pulses that each have received levels near 190 dB rms
(175-180 dB SEL) might result in cumulative exposure of approximately
186 dB SEL and thus slight TTS in a small odontocete, assuming the TTS
threshold is (to a first approximation) a function of the total
received pulse energy.
The above TTS information for odontocetes is derived from studies
on the bottlenose dolphin (Tursiops truncatus) and beluga whale
(Delphinapterus leucas). There is no published TTS information for
other species of cetaceans. However, preliminary evidence from a harbor
porpoise exposed to pulsed sound suggests that its TTS threshold may
have been lower (Lucke et al., 2009). As summarized above, data that
are now available imply that TTS is unlikely to occur unless
odontocetes are exposed to pile driving pulses stronger than 180 dB re
1 [mu]Pa rms.
Permanent Threshold Shift--When PTS occurs, there is physical
damage to the sound receptors in the ear. In severe cases, there can be
total or partial deafness, while in other cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985). There is no specific evidence that exposure to pulses of sound
can cause PTS in any marine mammal. However, given the possibility that
mammals close to a sound source might incur TTS, there has been further
speculation about the possibility that some individuals might incur
PTS. Single or occasional occurrences of mild TTS are not indicative of
permanent auditory damage, but repeated or (in some cases) single
exposures to a level well above that causing TTS onset might elicit
PTS.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals but are assumed to be similar to those in humans and
other terrestrial mammals. PTS might occur at a received sound level at
least several decibels above that inducing mild TTS if the animal were
exposed to strong sound pulses with rapid rise time. Based on data from
terrestrial mammals, a precautionary assumption is that the PTS
threshold for impulse sounds (such as pile driving pulses as received
close to the source) is at least 6 dB higher than the TTS threshold on
a peak-pressure basis and probably greater than 6 dB (Southall et al.,
2007). On an SEL basis, Southall et al. (2007) estimated that received
levels would need to exceed the TTS threshold by at least 15 dB for
there to be risk of PTS. Thus, for cetaceans, Southall et al. (2007)
estimate that the PTS threshold might be an M-
[[Page 22487]]
weighted SEL (for the sequence of received pulses) of approximately 198
dB re 1 [mu]Pa\2\-s (15 dB higher than the TTS threshold for an
impulse). Given the higher level of sound necessary to cause PTS as
compared with TTS, it is considerably less likely that PTS could occur.
Measured source levels from impact pile driving can be as high as
214 dB rms. Although no marine mammals have been shown to experience
TTS or PTS as a result of being exposed to pile driving activities,
captive bottlenose dolphins and beluga whales exhibited changes in
behavior when exposed to strong pulsed sounds (Finneran et al., 2000,
2002, 2005). The animals tolerated high received levels of sound before
exhibiting aversive behaviors. Experiments on a beluga whale showed
that exposure to a single watergun impulse at a received level of 207
kPa (30 psi) p-p, which is equivalent to 228 dB p-p, resulted in a 7
and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, respectively.
Thresholds returned to within 2 dB of the pre-exposure level within
four minutes of the exposure (Finneran et al., 2002). Although the
source level of pile driving from one hammer strike is expected to be
much lower than the single watergun impulse cited here, animals being
exposed for a prolonged period to repeated hammer strikes could receive
more sound exposure in terms of SEL than from the single watergun
impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the aforementioned
experiment (Finneran et al., 2002). However, in order for marine
mammals to experience TTS or PTS, the animals have to be close enough
to be exposed to high intensity sound levels for a prolonged period of
time. Based on the best scientific information available, these SPLs
are far below the thresholds that could cause TTS or the onset of PTS.
Non-auditory Physiological Effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to strong underwater sound include stress, neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies
examining such effects are limited. In general, little is known about
the potential for pile driving to cause auditory impairment or other
physical effects in marine mammals. Available data suggest that such
effects, if they occur at all, would presumably be limited to short
distances from the sound source and to activities that extend over a
prolonged period. The available data do not allow identification of a
specific exposure level above which non-auditory effects can be
expected (Southall et al., 2007) or any meaningful quantitative
predictions of the numbers (if any) of marine mammals that might be
affected in those ways. Marine mammals that show behavioral avoidance
of pile driving, including some odontocetes and some pinnipeds, are
especially unlikely to incur auditory impairment or non-auditory
physical effects.
Disturbance Reactions
Disturbance includes a variety of effects, including subtle changes
in behavior, more conspicuous changes in activities, and displacement.
Behavioral responses to sound are highly variable and context-specific
and reactions, if any, depend on species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day, and many other factors (Richardson et al., 1995; Wartzok
et al., 2003; Southall et al., 2007).
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. 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. Behavioral state may affect the type of response as well. For
example, animals that are resting may show greater behavioral change in
response to disturbing sound levels than animals that are highly
motivated to remain in an area for feeding (Richardson et al., 1995;
NRC, 2003; Wartzok et al., 2003).
Controlled experiments with captive marine mammals showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources
(typically seismic guns or acoustic harassment devices, but also
including pile driving) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; Thorson and Reyff, 2006; see also Gordon et al., 2004;
Wartzok et al., 2003; Nowacek et al., 2007). Responses to continuous
sound, such as vibratory pile installation, have not been documented as
well as responses to pulsed sounds.
With both types of pile driving, it is likely that the onset of
pile driving could result in temporary, short term changes in an
animal's typical behavior and/or avoidance of the affected area. These
behavioral changes may include (Richardson et al., 1995): Changing
durations of surfacing and dives, number of blows per surfacing, or
moving direction and/or speed; reduced/increased vocal activities;
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping); avoidance of
areas where sound sources are located; and/or flight responses (e.g.,
pinnipeds flushing into water from haul-outs or rookeries). Pinnipeds
may increase their haul-out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, or reproduction. Significant
behavioral modifications that could potentially lead to effects on
growth, survival, or reproduction include:
Drastic changes in diving/surfacing patterns (such as
those thought to cause beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al., 2007).
Auditory Masking
Natural and artificial sounds can disrupt behavior by masking, or
interfering with, a marine mammal's ability to hear other sounds.
Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher levels. Chronic exposure to excessive, though not high-
intensity, sound could cause masking at particular frequencies for
marine mammals that utilize sound for vital biological functions.
Masking can interfere with detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, under certain circumstances,
marine mammals
[[Page 22488]]
whose acoustical sensors or environment are being severely masked could
also be impaired from maximizing their performance fitness in survival
and reproduction. If the coincident (masking) sound were man-made, it
could be potentially harassing if it disrupted hearing-related
behavior. It is important to distinguish TTS and PTS, which persist
after the sound exposure, from masking, which occurs during the sound
exposure. Because masking (without resulting in TS) is not associated
with abnormal physiological function, it is not considered a
physiological effect, but rather a potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. Because sound
generated from in-water pile driving is mostly concentrated at low
frequency ranges, it may have less effect on high frequency
echolocation sounds made by porpoises. However, lower frequency man-
made sounds are more likely to affect detection of communication calls
and other potentially important natural sounds such as surf and prey
sound. It may also affect communication signals when they occur near
the sound band and thus reduce the communication space of animals
(e.g., Clark et al., 2009) and cause increased stress levels (e.g.,
Foote et al., 2004; Holt et al., 2009).
Masking has the potential to impact species at the population or
community levels as well as at individual levels. Masking affects both
senders and receivers of the signals and can potentially have long-term
chronic effects on marine mammal species and populations. Recent
research suggests that low frequency ambient sound levels have
increased by as much as 20 dB (more than three times in terms of SPL)
in the world's ocean from pre-industrial periods, and that most of
these increases are from distant shipping (Hildebrand, 2009). All
anthropogenic sound sources, such as those from vessel traffic, pile
driving, and dredging activities, contribute to the elevated ambient
sound levels, thus intensifying masking.
The most intense underwater sounds in the proposed action are those
produced by impact pile driving. Given that the energy distribution of
pile driving covers a broad frequency spectrum, sound from these
sources would likely be within the audible range of marine mammals
present in the project area. Impact pile driving activity is relatively
short-term, with rapid pulses occurring for approximately fifteen
minutes per pile. The probability for impact pile driving resulting
from this proposed action masking acoustic signals important to the
behavior and survival of marine mammal species is likely to be
negligible. Vibratory pile driving is also relatively short-term, with
rapid oscillations occurring for approximately one and a half hours per
pile. It is possible that vibratory pile driving resulting from this
proposed action may mask acoustic signals important to the behavior and
survival of marine mammal species, but the short-term duration and
limited affected area would result in insignificant impacts from
masking. Any masking event that could possibly rise to Level B
harassment under the MMPA would occur concurrently within the zones of
behavioral harassment already estimated for vibratory and impact pile
driving, and which have already been taken into account in the exposure
analysis.
Acoustic Effects, Airborne
Marine mammals that occur in the project area could be exposed to
airborne sounds associated with pile driving that have the potential to
cause harassment, depending on their distance from pile driving
activities. Airborne pile driving sound would have less impact on
cetaceans than pinnipeds because sound from atmospheric sources does
not transmit well underwater (Richardson et al., 1995); thus, airborne
sound would only be an issue for pinnipeds either hauled-out or looking
with heads above water in the project area. 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 their habitat and move further from the source. Studies by
Blackwell et al. (2004) and Moulton et al. (2005) indicate a tolerance
or lack of response to unweighted airborne sounds as high as 112 dB
peak and 96 dB rms.
Anticipated Effects on Habitat
The proposed activities at NBKB would not result in permanent
impacts to habitats used directly by marine mammals, such as haul-out
sites, but may have potential short-term impacts to food sources such
as forage fish and salmonids. There are no rookeries or major haul-out
sites within 16 km or ocean bottom structure of significant biological
importance to marine mammals that may be present in the marine waters
in the vicinity of the project area. Therefore, the main impact
associated with the proposed activity would be temporarily elevated
sound levels and the associated direct effects on marine mammals, as
discussed previously in this document. The most likely impact to marine
mammal habitat occurs from pile driving effects on likely marine mammal
prey (i.e., fish) near NBKB and minor impacts to the immediate
substrate during installation and removal of piles during the wharf
maintenance project.
Pile Driving Effects on Potential Prey
Construction activities would produce both pulsed (i.e., impact
pile driving) and continuous (i.e., vibratory pile driving) sounds.
Fish react to sounds which are especially strong and/or intermittent
low-frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution. Hastings and
Popper (2005) identified several studies that suggest fish may relocate
to avoid certain areas of sound energy. Additional studies have
documented effects of pile driving on fish, although several are based
on studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound
pulses at received levels of 160 dB may cause subtle changes in fish
behavior. SPLs of 180 dB may cause noticeable changes in behavior
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient
strength have been known to cause injury to fish and fish mortality.
The most likely impact to fish from pile driving activities at the
project area would be temporary behavioral avoidance 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 short
timeframe for the wharf maintenance project. However, adverse impacts
may occur to a few species of rockfish and salmon which may still be
present in the project area despite operating in a reduced work window
in an attempt to avoid important fish spawning time periods. Impacts to
these species could result from potential impacts to their eggs and
larvae.
Pile Driving Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in the Hood Canal. Avoidance by
potential prey (i.e., fish) of the immediate area due to the temporary
loss of this foraging habitat is also possible. The duration of fish
[[Page 22489]]
avoidance of this area after pile driving stops is unknown, but a rapid
return to normal recruitment, distribution and behavior is anticipated.
Any behavioral avoidance by fish of the disturbed area would still
leave significantly large areas of fish and marine mammal foraging
habitat in the Hood Canal and nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Thus, any impacts to marine mammal
habitat are not expected to cause significant or long-term consequences
for individual marine mammals or their populations.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses.
Measurements from similar pile driving events, including from
previously monitored construction activity on the NBKB waterfront, were
coupled with practical spreading loss to estimate zones of influence
(ZOI; see ``Estimated Take by Incidental Harassment''). These values
were then used to develop mitigation measures for EHW-1 pile driving
activities. The ZOIs effectively represent the mitigation zone that
would be established around each pile to prevent Level A harassment to
marine mammals, while providing estimates of the areas within which
Level B harassment might occur. While the ZOIs vary between the
different diameter piles and types of installation methods, the Navy is
proposing to establish mitigation zones for the maximum ZOI for all
pile driving conducted in support of the wharf maintenance project. In
addition to the measures described later in this section, the Navy
would conduct briefings between construction supervisors and crews,
marine mammal monitoring team, and Navy staff prior to the start of all
pile driving activity, and when new personnel join the work, in order
to explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
Monitoring and Shutdown for Pile Driving
The following measures would apply to the Navy's mitigation through
shutdown and disturbance zones:
Shutdown Zone--For all pile driving activities, the Navy will
establish a shutdown zone intended to contain the area in which SPLs
equal or exceed the 180/190 dB rms acoustic injury criteria. The
purpose of a shutdown zone is 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), thus preventing
injury of marine mammals. Modeled distances for shutdown zones are
shown in Table 4. The Navy would implement a minimum shutdown zone of
29 m radius for cetaceans and 10 m radius for pinnipeds around all pile
driving activity. However, no cetaceans have been observed within the
floating port security barrier, which is approximately 500 m from the
wharf.
Disturbance Zone--Disturbance zones are the areas in which SPLs
equal or exceed 160 and 120 dB rms (for pulsed and non-pulsed
continuous sound, respectively). Disturbance zones provide utility for
monitoring conducted for mitigation purposes (i.e., shutdown zone
monitoring) by establishing monitoring protocols for areas adjacent to
the shutdown zones. Monitoring of disturbance zones enables observers
to be aware of and communicate the presence of marine mammals in the
project area but outside the shutdown zone and thus prepare for
potential shutdowns of activity. However, the primary purpose of
disturbance zone monitoring is for documenting incidents of Level B
harassment; disturbance zone monitoring is discussed in greater detail
later (see ``Proposed Monitoring and Reporting''). Nominal radial
distances for disturbance zones are shown in Table 4. Given the size of
the disturbance zone for vibratory pile driving, it is impossible to
guarantee that all animals would be observed or to make comprehensive
observations of fine-scale behavioral reactions to sound, and only a
portion of the zone (e.g., what may be reasonably observed by visual
observers stationed within the water front restricted area [WRA]) will
be monitored.
In order to document observed incidents of harassment, monitors
record all marine mammal observations, regardless of location. The
observer's location, as well as the location of the pile being driven,
is known from a GPS. The location of the animal is estimated as a
distance from the observer, which is then compared to the location from
the pile. The received level may be estimated on the basis of past or
subsequent acoustic monitoring. It may then be determined whether the
animal was exposed to sound levels constituting incidental harassment
in post-processing of observational data, and a precise accounting of
observed incidents of harassment created. Therefore, although the
predicted distances to behavioral harassment thresholds are useful for
estimating harassment for purposes of authorizing levels of incidental
take, actual take may be determined in part through the use of
empirical data. That information may then be used to extrapolate
observed takes to reach an approximate understanding of actual total
takes.
Monitoring Protocols--Monitoring would be conducted before, during,
and after pile driving activities. In addition, observers shall record
all incidents of marine mammal occurrence, regardless of distance from
activity, and shall document any behavioral reactions in concert with
distance from piles being driven. Observations made outside the
shutdown zone will not result in shutdown; that pile segment would be
completed without cessation, unless the animal approaches or enters the
shutdown zone, at which point all pile driving activities would be
halted. Monitoring will take place from fifteen minutes prior to
initiation through thirty minutes post-completion of pile driving
activities. Pile driving activities include the time to 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 thirty minutes. Please see
the Marine Mammal Monitoring Plan (available at www.nmfs.noaa.gov/pr/permits/incidental/ and as Appendix C of the Navy's application),
developed by the Navy with our approval, for full details of the
monitoring protocols.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Qualified observers
are trained biologists, with the following minimum qualifications:
Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
[[Page 22490]]
Advanced education in biological science or related field
(undergraduate degree or higher required);
Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior; and
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.
(2) Prior to the start of pile driving activity, the shutdown zone
will be monitored for fifteen minutes to ensure that it is clear of
marine mammals. Pile driving will only commence once observers have
declared the shutdown zone clear of marine mammals; animals will be
allowed to remain in the shutdown zone (i.e., must leave of their own
volition) and their behavior will be monitored and documented. The
shutdown zone may only be declared clear, and pile driving started,
when the entire shutdown zone is visible (i.e., when not obscured by
dark, rain, fog, etc.). In addition, if such conditions should arise
during impact pile driving that is already underway, the activity would
be halted.
(3) If a marine mammal approaches or enters the shutdown zone
during the course of pile driving operations, activity will be halted
and delayed until either the animal has voluntarily left and been
visually confirmed beyond the shutdown zone or fifteen minutes have
passed without re-detection of the animal. Monitoring will be conducted
throughout the time required to drive a pile.
Sound Attenuation Devices
Sound levels can be greatly reduced during impact pile driving
using sound attenuation devices. There are several types of sound
attenuation devices including bubble curtains, cofferdams, and
isolation casings (also called temporary noise attenuation piles
[TNAP]), and cushion blocks. The Navy proposes to use bubble curtains,
which create a column of air bubbles rising around a pile from the
substrate to the water surface. The air bubbles absorb and scatter
sound waves emanating from the pile, thereby reducing the sound energy.
Bubble curtains may be confined or unconfined. An unconfined bubble
curtain may consist of a ring seated on the substrate and emitting air
bubbles from the bottom. An unconfined bubble curtain may also consist
of a stacked system, that is, a series of multiple rings placed at the
bottom and at various elevations around the pile. Stacked systems may
be more effective than non-stacked systems in areas with high current
and deep water (Oestman et al., 2009).
A confined bubble curtain contains the air bubbles within a
flexible or rigid sleeve made from plastic, cloth, or pipe. Confined
bubble curtains generally offer higher attenuation levels than
unconfined curtains because they may physically block sound waves and
they prevent air bubbles from migrating away from the pile. For this
reason, the confined bubble curtain is commonly used in areas with high
current velocity (Oestman et al., 2009).
Both environmental conditions and the characteristics of the sound
attenuation device may influence the effectiveness of the device.
According to Oestman et al. (2009):
In general, confined bubble curtains attain better sound
attenuation levels in areas of high current than unconfined bubble
curtains. If an unconfined device is used, high current velocity may
sweep bubbles away from the pile, resulting in reduced levels of sound
attenuation.
Softer substrates may allow for a better seal for the
device, preventing leakage of air bubbles and escape of sound waves.
This increases the effectiveness of the device. Softer substrates also
provide additional attenuation of sound traveling through the
substrate.
Flat bottom topography provides a better seal, enhancing
effectiveness of the sound attenuation device, whereas sloped or
undulating terrain reduces or eliminates its effectiveness.
Air bubbles must be close to the pile; otherwise, sound
may propagate into the water, reducing the effectiveness of the device.
Harder substrates may transmit ground-borne sound and
propagate it into the water column.
The literature presents a wide array of observed attenuation
results for bubble curtains (e.g., Oestman et al., 2009; Coleman, 2011;
see Appendix B of the Navy's application). The variability in
attenuation levels is due to variation in design, as well as
differences in site conditions and difficulty in properly installing
and operating in-water attenuation devices. As a general rule,
reductions of greater than 10 dB cannot be reliably predicted. The TPP
reported a range of measured values for realized attenuation mostly
within 6 to 12 dB (Illingworth & Rodkin, 2012). For 36-in piles the
average peak and rms reduction with use of the bubble curtain was 8 dB,
where the averages of all bubble-on and bubble-off data were compared.
For 48-in piles, the average SPL reduction with use of a bubble curtain
was 6 dB for average peak values and 5 dB for rms values.
To avoid loss of attenuation from design and implementation errors,
the Navy has required specific bubble curtain design specifications,
including testing requirements for air pressure and flow prior to
initial impact hammer use, and a requirement for placement on the
substrate. We considered TPP measurements (approximately 7 dB overall)
and other monitored projects (typically at least 8 dB realized
attenuation), and consider 8 dB as potentially a reasonable estimate of
average SPL (rms) reduction, assuming appropriate deployment and no
problems with the equipment.
Bubble curtains shall be used during all impact pile driving. The
device will distribute air bubbles around one hundred percent of the
piling perimeter for the full depth of the water column, and the lowest
bubble ring shall be in contact with the mudline for the full
circumference of the ring. Testing of the device by comparing
attenuated and unattenuated strikes is not possible because of
requirements in place to protect marbled murrelets (an ESA-listed bird
species under the jurisdiction of the USFWS). However, in order to
avoid loss of attenuation from design and implementation errors in the
absence of such testing, a performance test of the device shall be
conducted prior to initial use. The performance test shall confirm the
calculated pressures and flow rates at each manifold ring. In addition,
the contractor shall also train personnel in the proper balancing of
air flow to the bubblers and shall submit an inspection/performance
report to the Navy within 72 hours following the performance test.
[[Page 22491]]
Timing Restrictions
In Hood Canal, designated timing restrictions exist for pile
driving activities to avoid in-water work when salmonids and other
spawning forage fish are likely to be present. The in-water work window
is July 16-January 15. Until September 23, impact pile driving will
only occur starting two hours after sunrise and ending two hours before
sunset due to marbled murrelet nesting season. After September 23, in-
water construction activities will occur during daylight hours (sunrise
to sunset).
Soft Start
The use of a soft-start procedure is believed to provide additional
protection to marine mammals by warning or providing a chance to leave
the area prior to the hammer operating at full capacity, and typically
involves a requirement to initiate sound from vibratory hammers for
fifteen seconds at reduced energy followed by a thirty-second waiting
period. This procedure is repeated two additional times.
However, implementation of soft start for vibratory pile driving
during previous pile driving work for the EHW-2 project at NBKB has led
to equipment failure and serious human safety concerns. Project staff
have reported that, during power down from the soft start, the energy
from the hammer is transferred to the crane boom and block via the load
fall cables and rigging resulting in unexpected damage to both the
crane block and crane boom. This differs from what occurs when the
hammer is powered down after a pile is driven to refusal in that the
rigging and load fall cables are able to be slacked prior to powering
down the hammer, and the vibrations are transferred into the substrate
via the pile rather than into the equipment via the rigging. One
dangerous incident of equipment failure has already occurred, with a
portion of the equipment shearing from the crane and falling to the
deck. Subsequently, the crane manufacturer has inspected the crane
booms and discovered structural fatigue in the boom lacing and main
structural components, which will ultimately result in a collapse of
the crane boom. All cranes were new at the beginning of the job. In
addition, the vibratory hammer manufacturer has attempted to install
dampers to mitigate the problem, without success. In consultation with
the Navy and experts in the field of marine construction, it was
determined that the likely cause of the issue was that larger vibratory
hammers (e.g., APE Model 600) are not designed to handle the additional
vibration resulting from the soft start procedure. Large hammers were
required due to the design specifications of the EHW-2, but are not
expected to be necessary for the EHW-1 maintenance work. Use of smaller
variable moment style vibratory hammers has not resulted in similar
issues to date.
Therefore, vibratory soft start will be required as previously
described. However, if a variable moment hammer proves infeasible for
use with this project, or if unsafe working conditions during soft
starts are reported by the contractor and verified by an independent
safety inspection, the Navy may discontinue use of the vibratory soft
start measure.
For impact driving, soft start will be required, and contractors
will provide an initial set of strikes from the impact hammer at
reduced energy, followed by a thirty-second waiting period, then two
subsequent reduced energy strike sets. The reduced energy of an
individual hammer cannot be quantified because of variation in
individual drivers. The actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes.'' Soft start for impact driving will be required at
the beginning of each day's pile driving work and at any time following
a cessation of impact pile driving of thirty minutes or longer.
We have carefully evaluated the Navy's proposed mitigation measures
and considered their effectiveness in past implementation to
preliminarily determine whether they are likely to effect the least
practicable impact on the affected marine mammal species and stocks and
their habitat. Our evaluation of potential measures included
consideration of the following factors in relation to one another: (1)
The manner in which, and the degree to which, the successful
implementation of the measure is expected to minimize adverse impacts
to marine mammals, (2) the proven or likely efficacy of the specific
measure to minimize adverse impacts as planned; and (3) the
practicability of the measure for applicant implementation.
Any mitigation measure(s) we prescribe should be able to
accomplish, have a reasonable likelihood of accomplishing (based on
current science), or contribute to the accomplishment of one or more of
the general goals listed below:
(1) Avoidance or minimization of injury or death of marine mammals
wherever possible (goals 2, 3, and 4 may contribute to this goal).
(2) A reduction in the number (total number or number at
biologically important time or location) of individual marine mammals
exposed to stimuli expected to result in incidental take (this goal may
contribute to 1, above, or to reducing takes by behavioral harassment
only).
(3) A reduction in the number (total number or number at
biologically important time or location) of times any individual marine
mammal would be exposed to stimuli expected to result in incidental
take (this goal may contribute to 1, above, or to reducing takes by
behavioral harassment only).
(4) A reduction in the intensity of exposure to stimuli expected to
result in incidental take (this goal may contribute to 1, above, or to
reducing the severity of behavioral harassment only).
(5) Avoidance or minimization of adverse effects to marine mammal
habitat, paying particular attention to the prey base, blockage or
limitation of passage to or from biologically important areas,
permanent destruction of habitat, or temporary disturbance of habitat
during a biologically important time.
(6) For monitoring directly related to mitigation, an increase in
the probability of detecting marine mammals, thus allowing for more
effective implementation of the mitigation.
Based on our evaluation of the Navy's proposed measures, including
information from monitoring of the Navy's implementation of the
mitigation measures as prescribed under previous IHAs for this and
other projects in the Hood Canal, we have preliminarily determined that
the proposed mitigation measures provide the means of effecting the
least practicable impact on marine mammal 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
incidental take authorizations must include the suggested means of
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species and of the level of taking or
impacts on populations of marine mammals that are expected to be
present in the proposed action area.
[[Page 22492]]
Any monitoring requirement we prescribe should accomplish one or
more of the following general goals:
1. An increase in the probability of detecting marine mammals, both
within defined zones of effect (thus allowing for more effective
implementation of the mitigation) and in general to generate more data
to contribute to the analyses mentioned below;
2. An increase in our understanding of how many marine mammals are
likely to be exposed to stimuli that we associate with specific adverse
effects, such as behavioral harassment or hearing threshold shifts;
3. An increase in our understanding of how marine mammals respond
to stimuli expected to result in incidental take and how anticipated
adverse effects on individuals may impact the population, stock, or
species (specifically through effects on annual rates of recruitment or
survival) through any of the following methods:
Behavioral observations in the presence of stimuli
compared to observations in the absence of stimuli (need to be able to
accurately predict pertinent information, e.g., received level,
distance from source);
Physiological measurements in the presence of stimuli
compared to observations in the absence of stimuli (need to be able to
accurately predict pertinent information, e.g., received level,
distance from source);
Distribution and/or abundance comparisons in times or
areas with concentrated stimuli versus times or areas without stimuli;
4. An increased knowledge of the affected species; or
5. An increase in our understanding of the effectiveness of certain
mitigation and monitoring measures.
The Navy submitted a marine mammal monitoring plan as part of their
IHA application, and can be found on the Internet at www.nmfs.noaa.gov/pr/permits/incidental/. Similar plans have been successfully
implemented by the Navy under previous IHAs issued for work conducted
at NBKB and the plan may be modified or supplemented based on comments
or new information received from the public during the public comment
period.
Visual Marine Mammal Observations
The Navy will collect sighting data and behavioral responses to
construction for marine mammal species observed in the region of
activity during the period of activity. All observers will be trained
in marine mammal identification and behaviors and are required to have
no other construction-related tasks while conducting monitoring. The
Navy will monitor the shutdown zone and disturbance zone before,
during, and after pile driving, with observers located at the best
practicable vantage points. Based on our requirements, the Marine
Mammal Monitoring Plan would implement the following procedures for
pile driving:
A dedicated monitoring coordinator will be on-site during
all construction days. The monitoring coordinator will oversee marine
mammal observers. The monitoring coordinator will serve as the liaison
between the marine mammal monitoring staff and the construction
contractor to assist in the distribution of information.
MMOs would be located at the best vantage point(s) in
order to properly see the entire shutdown zone and as much of the
disturbance zone as possible. A minimum of three MMOs will be on duty
during all pile driving activity, with two of these monitoring the
shutdown zones.
During all observation periods, observers will use
binoculars and the naked eye to search continuously for marine mammals.
If the shutdown zones are obscured by fog or poor lighting
conditions, pile driving at that location will not be initiated until
that zone is visible. Should such conditions arise while impact driving
is underway, the activity would be halted.
The shutdown and disturbance zones around the pile will be
monitored for the presence of marine mammals before, during, and after
any pile driving or removal activity.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. Monitoring biologists will
use their best professional judgment throughout implementation and seek
improvements to these methods when deemed appropriate. Any
modifications to protocol will be coordinated between NMFS and the
Navy.
Data Collection
We require that observers use approved data forms. Among other
pieces of information, the Navy will record detailed information about
any implementation of shutdowns, including the distance of animals to
the pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, the Navy will attempt to
distinguish between the number of individual animals taken and the
number of incidents of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report would be submitted within ninety calendar days of
the completion of the in-water work window. The report will include
marine mammal observations pre-activity, during-activity, and post-
activity during pile driving days, and will also provide descriptions
of any problems encountered in deploying sound attenuating devices, any
behavioral responses to construction activities by marine mammals and a
complete description of all mitigation shutdowns and the results of
those actions and an extrapolated total take estimate based on the
number of marine mammals observed during the course of construction. A
final report must be submitted within thirty days following resolution
of comments on the draft report.
Estimated Take by Incidental Harassment
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].''
All anticipated takes would be by Level B harassment resulting from
vibratory and impact pile driving and involving temporary changes in
behavior. The proposed mitigation and monitoring measures are expected
to minimize the possibility of injurious or
[[Page 22493]]
lethal takes such that take by Level A harassment, serious injury, or
mortality is considered discountable. However, it is unlikely that
injurious or lethal takes would occur even in the absence of the
planned mitigation and monitoring measures.
If a marine mammal responds to a stimulus by changing its behavior
(e.g., through relatively minor changes in locomotion direction/speed
or vocalization behavior), the response may or may not constitute
taking at the individual level, and is unlikely to affect the stock or
the species as a whole. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on animals or on the stock or species could potentially
be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007). Given
the many uncertainties in predicting the quantity and types of impacts
of sound on marine mammals, it is common practice to estimate how many
animals are likely to be present within a particular distance of a
given activity, or exposed to a particular level of sound.
This practice potentially overestimates the numbers of marine
mammals taken. For example, during the past fifteen years, killer
whales have been observed within the project area twice. On the basis
of that information, an estimated amount of potential takes for killer
whales is presented here. However, while a pod of killer whales could
potentially visit again during the project timeframe, and thus be
taken, it is more likely that they will not. Although incidental take
of killer whales has been authorized under past IHAs for activities at
NBKB on the basis of past observations of these species, no such takes
have been recorded and no individuals of these species have been
observed. Similarly, estimated actual take levels (observed takes
extrapolated to the remainder of unobserved but ensonified area) were
significantly less than authorized levels of take for the remaining
species. In addition, it is often difficult to distinguish between the
individuals harassed and incidences of harassment. In particular, for
stationary activities, it is more likely that some smaller number of
individuals may accrue a number of incidences of harassment per
individual than for each incidence to accrue to a new individual,
especially if those individuals display some degree of residency or
site fidelity and the impetus to use the site (e.g., because of
foraging opportunities) is stronger than the deterrence presented by
the harassing activity.
The project area is not believed to be particularly important
habitat for marine mammals, nor is it considered an area frequented by
marine mammals, although harbor seals are year-round residents of Hood
Canal and sea lions are known to haul-out on submarines and other man-
made objects at the NBKB waterfront (although typically at a distance
of a mile or greater from the project site). Therefore, behavioral
disturbances that could result from anthropogenic sound associated with
these activities are expected to affect only a relatively small number
of individual marine mammals, although those effects could be recurring
over the life of the project if the same individuals remain in the
project vicinity.
The Navy has requested authorization for the incidental taking of
small numbers of Steller sea lions, California sea lions, harbor seals,
transient killer whales, and harbor porpoises in the Hood Canal that
may result from pile driving during construction activities associated
with the wharf maintenance project described previously in this
document. In order to estimate the potential incidents of take that may
occur incidental to the specified activity, we must first estimate the
extent of the sound field that may be produced by the activity and then
consider in combination with information about marine mammal density or
abundance in the project area. We first provide information on
applicable sound thresholds for determining effects to marine mammals
before describing the information used in estimating the sound fields,
the available marine mammal density or abundance information, and the
method of estimating potential incidences of take.
Sound Thresholds
We use generic sound exposure thresholds to determine when an
activity that produces sound might result in impacts to a marine mammal
such that a take by harassment might occur. To date, no studies have
been conducted that explicitly examine impacts to marine mammals from
pile driving sounds or from which empirical sound thresholds have been
established. These thresholds should be considered guidelines for
estimating when harassment may occur (i.e., when an animal is exposed
to levels equal to or exceeding the relevant criterion) in specific
contexts; however, useful contextual information that may inform our
assessment of effects is typically lacking and we consider these
thresholds as step functions. NMFS is currently revising these acoustic
guidelines; for more information on that process, please visit
www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. Vibratory pile driving
produces non-pulsed noise and impact pile driving produces impulsive
noise.
Table 3--Current Acoustic Exposure Criteria
------------------------------------------------------------------------
Criterion Definition Threshold
------------------------------------------------------------------------
Level A harassment (underwater). Injury (PTS--any 180 dB (cetaceans)/
level above that 190 dB
which is known to (pinnipeds)
cause TTS). (rms).
Level B harassment (underwater). Behavioral 160 dB (impulsive
disruption. source)/120 dB
(continuous
source) (rms).
Level B harassment (airborne)*.. Behavioral 90 dB (harbor
disruption. seals)/100 dB
(other pinnipeds)
(unweighted).
------------------------------------------------------------------------
* NMFS has not established any formal criteria for harassment resulting
from exposure to airborne sound. However, these thresholds represent
the best available information regarding the effects of pinniped
exposure to such sound and NMFS' practice is to associate exposure at
these levels with Level B harassment.
Distance to Sound Thresholds
Underwater Sound Propagation Formula--Pile driving generates
underwater noise that can potentially result in disturbance to marine
mammals in the project area. Transmission loss (TL) is the decrease in
acoustic intensity as an acoustic pressure wave propagates out from a
source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and
bottom composition and topography. The general formula for underwater
TL is:
[[Page 22494]]
TL = B * log10(R1/R2), where
R1 = the distance of the modeled SPL from the driven pile,
and
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of fifteen is often used under conditions,
such as Hood Canal, where water increases with depth as the receiver
moves away from the shoreline, resulting in an expected propagation
environment that would lie between spherical and cylindrical spreading
loss conditions. Practical spreading loss (4.5 dB reduction in sound
level for each doubling of distance) is assumed here.
Underwater Sound--The intensity of pile driving sounds is greatly
influenced by factors such as the type of piles, hammers, and the
physical environment in which the activity takes place. A large
quantity of literature regarding SPLs recorded from pile driving
projects is available for consideration. In order to determine
reasonable SPLs and their associated effects on marine mammals that are
likely to result from pile driving at NBKB, studies with similar
properties to the specified activity were evaluated, including
measurements conducted for driving of steel piles at NBKB as part of
the TPP (Illingworth & Rodkin, 2012). Please see Appendix B of the
Navy's application for a detailed description of the information
considered in determining reasonable proxy source level values. The
Navy used representative source levels (for installation of 30-in steel
pipe pile) of 195 dB rms for impact driving and 166 dB rms for
vibratory driving. For impact driving, 8 dB effective attenuation was
assumed due to use of a bubble curtain and was therefore subtracted
from the source level.
We assume here that consideration of vibratory pile driving, and
that vibratory driving could occur on any of the eight days, is
conservative in relation to pile removal via pneumatic chipping.
Acoustic measurements for pneumatic chipping were previously performed
during maintenance work at EHW-1 in 2012. The average value measured at
10 m was 141 dB rms (RMDT, 2013). Therefore, we do not explicitly
consider pile removal (via pneumatic chipping) separately from pile
installation activity.
Table 4--Calculated Distance(s) to and Area Encompassed by Underwater
Marine Mammal Sound Thresholds During Pile Installation
------------------------------------------------------------------------
Threshold Distance Area
------------------------------------------------------------------------
Impact driving, pinniped injury 6 m............... 113 m\2\
(190 dB).
Impact driving, cetacean injury 29 m.............. 2,630 m\2\
(180 dB).
Impact driving, disturbance (160 631 m............. 0.9 km\2\
dB).
Vibratory driving, pinniped n/a............... --
injury (190 dB).
Vibratory driving, cetacean n/a............... --
injury (180 dB).
Vibratory driving, disturbance 6.3 km............ 32.4 km\2\
(120 dB).
------------------------------------------------------------------------
Hood Canal does not represent open water, or free field,
conditions. Therefore, sounds would attenuate as they encounter land
masses or bends in the canal. As a result, the calculated distance and
areas of impact for the 120-dB threshold cannot actually be attained at
the project area. See Figure 6-1 of the Navy's application for a
depiction of the size of areas in which each underwater sound threshold
is predicted to occur at the project area due to pile driving.
Airborne Sound--Pile driving can generate airborne sound that could
potentially result in disturbance to marine mammals (specifically,
pinnipeds) which are hauled out or at the water's surface. As a result,
the Navy analyzed the potential for pinnipeds hauled out or swimming at
the surface near NBKB to be exposed to airborne SPLs that could result
in Level B behavioral harassment. A spherical spreading loss model
(i.e., 6 dB reduction in sound level for each doubling of distance from
the source), in which there is a perfectly unobstructed (free-field)
environment not limited by depth or water surface, is appropriate for
use with airborne sound and was used to estimate the distance to the
airborne thresholds.
As was discussed for underwater sound from pile driving, the
intensity of pile driving sounds is greatly influenced by factors such
as the type of piles, hammers, and the physical environment in which
the activity takes place. In order to determine reasonable airborne
SPLs and their associated effects on marine mammals that are likely to
result from pile driving at NBKB, studies with similar properties to
the proposed action, as described previously, were evaluated. The Navy
used representative source levels of 112 dB Lmax
(unweighted) for impact driving (for 36-in steel pipe piles) and 95 dB
Lmax (unweighted) for vibratory driving (for 30-in steel
pipe piles). Please see Appendix B of the Navy's application for
details of the information considered. These values give a maximum
disturbance zone (radial distance) of 189 m for harbor seals and 60 m
for sea lions (see Table 6-6 in the Navy's application).
However, no incidents of incidental take resulting solely from
airborne sound are likely, as distances to the harassment thresholds
would not reach areas where pinnipeds may haul out. Harbor seals can
haul out at a variety of natural or manmade locations, but the closest
known harbor seal haul-out is at the Dosewallips River mouth (London,
2006) and Navy waterfront surveys and boat surveys have found it rare
for harbor seals to haul out along the NBKB waterfront (Agness and
Tannenbaum, 2009; Tannenbaum et al., 2009, 2011; DoN, 2013). Individual
seals have been observed hauled out on pontoons of the floating
security fence within the restricted areas of NBKB, but this area is
not within the airborne disturbance ZOI. Nearby piers are elevated well
above the surface of the water and are inaccessible to pinnipeds, and
seals have not been observed hauled out on the adjacent shoreline. Sea
lions typically haul out on submarines docked at Delta Pier,
approximately one mile from the project site.
We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with heads above water. However, these animals would previously have
been `taken' as a result of exposure to underwater sound above the
behavioral harassment thresholds, which are in all cases larger than
those associated with airborne sound. Thus, the behavioral harassment
of these animals is already accounted for in these estimates of
potential take. Multiple incidents of exposure to sound above NMFS'
thresholds for behavioral harassment are not believed to result in
increased behavioral disturbance, in either nature or intensity of
disturbance reaction. Therefore, we do not believe that authorization
of incidental take resulting from airborne sound for
[[Page 22495]]
pinnipeds is warranted, and airborne sound is not discussed further
here.
Marine Mammal Occurrence
The Navy has developed, with input from regional marine mammal
experts, estimates of marine mammal densities in Washington inland
waters for the Navy Marine Species Density Database (NMSDD). A
technical report (Hanser et al., 2014) describes methodologies and
available information used to derive these densities, which are
generally considered the best available information for Washington
inland waters, except where specific local abundance information is
available. With the exception of the harbor porpoise density (derived
from vessel-based surveys conducted in Hood Canal), we do not believe
the NMSDD density values are appropriate for use here, for the
following reasons: (1) Local abundance information exists for sea
lions, which regularly haul out at the NBKB waterfront; (2) harbor seal
density for Hood Canal has recently been revised as described below;
and (3) density values are not appropriate for rarely occurring
species, such as transient killer whales in Hood Canal. Please see
Appendix A of the Navy's application for more information about survey
effort at NBKB.
For all species, the most appropriate information available was
used to estimate the number of potential incidences of take. For harbor
seals, this involved published literature describing harbor seal
research conducted in Washington and Oregon, including counts and
research specific to Hood Canal (Huber et al., 2001; Jeffries et al.,
2003; London et al., 2012). Killer whales are known from two periods of
occurrence (2003 and 2005) and are not known to preferentially use any
specific portion of the Hood Canal. Therefore, potential occurrence was
assumed as likely maximum group size (Houghton et al., in prep.) in
concert with a nominal number of days present, in order to provide for
small possibility that killer whales could be present. The best
information available for the remaining species in Hood Canal came from
surveys conducted by the Navy at the NBKB waterfront or in the vicinity
of the project area (see Appendix A of the Navy's application).
Due to their occurrence in deeper waters of Hood Canal, this
analysis assumes that harbor porpoise are uniformly distributed in the
project area. However, it should be noted that there have been no
observations of cetaceans within the floating security barriers at
NBKB; these barriers thus appear to effectively prevent cetaceans from
approaching the shutdown zones. Although the Navy will implement a
precautionary shutdown zone for cetaceans, anecdotal evidence suggests
that cetaceans are not at risk of Level A harassment at NBKB even from
louder activities (e.g., impact pile driving). As described previously,
any potential occurrence of killer whales would be a rare event likely
consisting of a single group of whales. Harbor seals likely occur in
greater numbers of along the NBKB waterfront than in deeper waters of
Hood Canal, but are observed throughout the action area and through use
of a density value here we assume that they are uniformly distributed
(likely overestimating occurrence in the larger Level B harassment zone
for vibratory driving). The remaining species that occur in the project
area, Steller sea lion and California sea lion, do not appear to
utilize most of Hood Canal. The sea lions appear to be attracted to the
man-made haul-out opportunities along the NBKB waterfront while
dispersing for foraging opportunities elsewhere in Hood Canal.
California sea lions were not reported during aerial surveys of Hood
Canal (Jeffries et al., 2000), and Steller sea lions have been
documented almost solely at the NBKB waterfront.
Description of Take Calculation
The take calculations presented here rely on the best data
currently available for marine mammal populations in the Hood Canal.
The formula was developed for calculating take due to pile driving
activity and applied to each group-specific sound impact threshold. The
formula is founded on the following assumptions:
All marine mammal individuals potentially available are
assumed to be present within the relevant area, and thus incidentally
taken;
An individual can only be taken once during a 24-h period;
There were will be eight total days of activity and the
largest ZOI equals 32.4 km\2\;
Exposure modeling assumes that one impact pile driver and
three vibratory pile drivers are operating concurrently; and,
Exposures to sound levels above the relevant thresholds
equate to take, as defined by the MMPA.
The calculation for marine mammal takes is estimated by:
Exposure estimate = (n * ZOI) * days of total activity
Where:
n = density estimate used for each species/season
ZOI = sound threshold ZOI area; the area encompassed by all
locations where the SPLs equal or exceed the threshold being
evaluated
n * ZOI produces an estimate of the abundance of animals that could
be present in the area for exposure, and is rounded to the nearest
whole number before multiplying by days of total activity. Where simple
abundance is used, this value replaces the product of n * ZOI.
The ZOI impact area is the estimated range of impact to the sound
criteria. The relevant distances specified in Table 4 were used to
calculate ZOIs around each pile. The ZOI impact area took into
consideration the possible affected area of the Hood Canal from the
pile driving site furthest from shore with attenuation due to land
shadowing from bends in the canal. Because of the close proximity of
some of the piles to the shore, the narrowness of the canal at the
project area, and the maximum fetch, the ZOIs for each threshold are
not necessarily spherical and may be truncated.
While pile driving can occur any day throughout the in-water work
window, and the analysis is conducted on a per day basis, only a
fraction of that time (typically a matter of hours on any given day) is
actually spent pile driving. Also of note is the fact that the
effectiveness of mitigation measures in reducing takes is typically not
quantified in the take estimation process. In addition, equating
exposure with response (i.e., a behavioral response meeting the
definition of take under the MMPA) is a simplistic and conservative
assumption. For these reasons, these take estimates are likely to be
conservative. See Table 5 for total estimated incidents of take.
California Sea Lion--California sea lions occur regularly in the
vicinity of the project site, with the exception of approximately mid-
June through mid-August, as determined by Navy waterfront surveys
conducted from April 2008 through December 2013. The first California
sea lion was observed at NBKB in August 2009, and their occurrence has
been increasing since that time (DoN, 2013). With regard to the range
of this species in Hood Canal and the project area, we assume on the
basis of waterfront observations (Agness and Tannenbaum, 2009;
Tannenbaum et al., 2009, 2011; HDR 2012a, 2012b; Hart Crowser, 2013)
that the opportunity to haul out on submarines docked at Delta Pier is
a primary attractant for California sea lions in Hood Canal, as they
are not typically observed elsewhere in Hood Canal. Abundance is
calculated as the monthly average of the maximum number observed in a
given month, as
[[Page 22496]]
opposed to the overall average. That is, the maximum number of animals
observed on any one day in a given month was averaged for 2008-13,
providing a monthly average of the maximum daily number observed. The
largest monthly average (71 animals) was recorded in November, as was
the largest single daily count (122 animals). We conservatively assume
that a maximum of 71 California sea lions could be in the vicinity of
the action area and potentially subject to incidental harassment on
each of the maximum eight days of pile driving activity.
Steller Sea Lion--Steller sea lions were first documented at the
NBKB waterfront in November 2008, while hauled out on submarines at
Delta Pier, and have been periodically observed from October to April
since that time, as determined by Navy waterfront surveys conducted
from April 2008 through December 2013. Steller sea lions are
occasionally observed in early May or late September, but have never
been observed from approximately mid-May through mid-September. We
assume, on the basis of waterfront observations (Agness and Tannenbaum,
2009; Tannenbaum et al., 2009, 2011; HDR 2012a, 2012b; Hart Crowser,
2013), that Steller sea lions use available haul-outs and foraging
habitat similarly to California sea lions. On occasions when Steller
sea lions are observed, they typically occur in mixed groups with
California sea lions also present, allowing observers to confirm their
identifications based on discrepancies in size and other physical
characteristics.
Abundance is calculated in the same manner described for California
sea lions. That is, the maximum number of animals observed on any one
day in a given month was averaged for 2008-13, providing a monthly
average of the maximum daily number observed. The largest monthly
average (six animals) was recorded in November, as was the largest
single daily count (eleven animals). We conservatively assume that a
maximum of six Steller sea lions could be in the vicinity of the action
area and potentially subject to incidental harassment on each of the
maximum eight days of pile driving activity.
Harbor Seal--The harbor seal density used here is revised from that
in the NMSDD (Hanser et al., 2014), on the basis of information
regarding harbor seal haul-out behavior specific to Hood Canal (London
et al., 2012). Jeffries et al. (2003) conducted aerial surveys of
harbor seals in 1999 for the Washington Department of Fish and
Wildlife, dividing the survey areas into seven strata (including five
in inland waters and two in coastal waters). Survey effort in the Hood
Canal stratum yielded a count of 711 harbor seals hauled out. In order
to produce a total abundance estimate, a correction factor based on the
proportion of time seals spend on land versus in the water over the
course of a day must then be applied to account for animals in the
water and not observed during survey counts. Previous density estimates
used a correction factor of 1.53 (Huber et al., 2001) to derive a total
Hood Canal population of 1,088 seals. That factor was based on data
from tags (VHF transmitters) applied to harbor seals at six areas
(Grays Harbor, Tillamook Bay, Umpqua River, Gertrude Island,
Protection/Smith Islands, and Boundary Bay, BC) within two different
harbor seal stocks (the coastal stock and the Washington inland waters
stock) over four survey years. Although the sampling areas included
both coastal and inland waters, with pooled correction factors of 1.50
and 1.57, respectively, Huber et al. (2001) found no significant
difference in the proportion of seals ashore among the six sites and no
interannual variation at one site studied across years. The Hood Canal
population is part of the inland waters stock, and while not
specifically sampled, Jeffries et al. (2003) found the VHF data to be
broadly applicable to the entire Washington harbor seal population.
However, London et al. (2012) provide more recent data that is specific
to Hood Canal. This more recent tagging data indicates that harbor
seals in Hood Canal haul out only twenty percent of the time;
therefore, the 1999 aerial surveys are considered to represent only
twenty percent of the population, and the 1999 population estimate was
updated to approximately 3,555 animals. This abundance, considered with
the area of Hood Canal (358 km\2\), gives an abundance estimate of 9.9
animals/km\2\.
At any given time, some animals will be hauled out and some will be
in the water and, to determine an instantaneous in-water density
estimate, a secondary correction may be applied to account for harbor
seals that are hauled out at any given moment. The London et al. (2012)
data indicate that eighty percent of the population might be in the
water at a given time; therefore a corrected density was derived from
the number of harbor seals that are present in the water at any one
time (eighty percent of 3,555, or approximately 2,844 individuals),
divided by the area of the Hood Canal, yielding an estimate of 7.93
animals/km\2\.
We recognize that over the course of the day, while the proportion
of animals in the water may not vary significantly, different
individuals may enter and exit the water (i.e., it is probable that
greater than eighty percent of seals will enter the water at some point
during the day). Therefore, an instantaneous estimate of animals in the
water at a given time may not produce an accurate assessment of the
number of individuals that enter the water over the daily duration of
the activity. However, no data exist regarding fine-scale harbor seal
movements within the project area on time durations of less than a day,
thus precluding an assessment of ingress or egress of different animals
through the action area. As such, it is impossible, given available
data, to determine exactly what number of individuals above eighty
percent may potentially be exposed to underwater sound. Therefore, we
are left to make a decision, on the basis of limited available
information, regarding which of these two scenarios (i.e., one hundred
percent versus eighty percent of harbor seals are in the water and
exposed to sound) produces a more accurate estimate of the potential
incidents of take.
First, we understand that hauled-out harbor seals are necessarily
at haul-outs. No significant harbor seal haul-outs are located within
or near the action area. Harbor seals observed in the vicinity of the
NBKB shoreline are rarely hauled-out (for example, in formal surveys
during 2007-08, approximately 86 percent of observed seals were
swimming), and when hauled-out, they do so opportunistically (i.e., on
floating booms rather than established haul-outs). Harbor seals are
typically unsuited for using manmade haul-outs at NBKB, which are used
by the larger sea lions. Primary harbor seal haul-outs in Hood Canal
are generally located at significant distance (20 km or more) from the
action area in Dabob Bay or further south (see Figure 4-1 in the Navy's
application), meaning that animals casually entering the water from
haul-outs or flushing due to some disturbance at those locations would
not be exposed to underwater sound from the project; rather, only those
animals embarking on foraging trips and entering the action area may be
exposed.
Second, we know that harbor seals in Hood Canal are not likely to
have a uniform distribution as is assumed through use of a density
estimate, but are likely to be relatively concentrated near areas of
interest such as the haul-outs found in Dabob Bay or foraging areas.
The majority of the action area consists of the Level B harassment zone
[[Page 22497]]
in deeper waters of Hood Canal; past observations from surveys and
required monitoring have confirmed that harbor seals are less abundant
in these waters.
Third, a typical pile driving day (in terms of the actual time
spent driving) is somewhat shorter than may be assumed (i.e., 8-15
hours) as a representative pile driving day based on daylight hours.
Construction scheduling and notional production rates in concert with
typical delays mean that hammers are active for only some fraction of
time on pile driving ``days''. During recent years of construction at
NBKB, pile driving occurred for an approximate average of seven hours
per pile driving day.
What we know tells us that (1) the turnover of harbor seals (in and
out of the water) is occurring primarily outside the action area and
would not be expected to result in a greater number of individuals
entering the action area within a given day and being harassed than is
assumed; (2) there are likely to be significantly fewer harbor seals in
the majority of the action area than would be indicated by the
uncorrected density; and (3) pile driving actually occurs over a
limited timeframe on any given day (i.e., less total time per day than
would be assumed based on daylight hours and non-continuously),
reducing the amount of time over which new individuals might enter the
action area within a given day. These factors lead us to believe that
the corrected density is likely to more closely approximate the number
of seals that may be found in the action area than does the uncorrected
density, and there are no existing data that would indicate that the
proportion of individuals entering the water within the predicted area
of effect during pile driving would be dramatically larger than eighty
percent. Therefore, using one hundred percent of the population to
estimate density would likely result in an overestimate of potential
take. Moreover, because the Navy is typically unable to determine from
field observations whether the same or different individuals are being
exposed, each observation is recorded as a new take, although an
individual theoretically would only be considered as taken once in a
given day.
Finally, we note that during the course of previous IHAs issued for
Navy activity at NBKB, the total estimate of actual incidents of take
(observed takes and observations extrapolated to unobserved area) has
been substantially less than the estimated numbers of take. This is
almost certainly negatively biased, but the disparity does provide
confirmation that we are not significantly underestimating takes.
Killer Whales--Transient killer whales are uncommon visitors to
Hood Canal, and may be present anytime during the year. Transient pods
(six to eleven individuals per event) were observed in Hood Canal for
lengthy periods of time (59-172 days) in 2003 (January-March) and 2005
(February-June), feeding on harbor seals (London, 2006). These whales
used the entire expanse of Hood Canal for feeding. The NMSDD used
monthly unique sightings data collected over the period 2004-2010 and
an average group size of 5.16 (Houghton et al., in prep.) to calculate
densities on a seasonal basis for each of five geographic strata
(Hanser et al., 2014).
While transient killer whales are rare in the Hood Canal, it is
possible that a pod of animals could be present. In the event that this
occurred in a similar manner to prior occurrences (e.g., 59-172 days)
and incidental take were not authorized appropriately, there could be
significant project delays. In estimating potential incidences of take
here, we make three assumptions: (1) Transient killer whales have a
reasonable likelihood of occurrence in the project area; (2) if whales
were present, they would occur in a pod of six animals (the minimum pod
size seen in the 2003/2005 events but equivalent to the average pod
size reported by Houghton et al. [in prep.]); and (3) the pod would be
present and affected by project activities (i.e., within the larger
vibratory Level B harassment zone) for two of the maximum eight days.
We believe that it is unlikely the whales would remain in the area for
a longer period in the presence of a harassing stimulus (i.e., pile
driving). In the absence of any overriding contextual element (e.g.,
NBKB is not important as a breeding area, and provides no unusual
concentration of prey), it is reasonable to assume that whales would
leave the area if exposed to potentially harassing levels of sound on
each day that they were present. In summary, we assume here that, if
killer whales occurred in the project area, a pod of six whales would
be present--and could potentially be harassed--for two days.
Harbor Porpoise--During vessel-based line transect surveys on non-
construction days during the TPP, harbor porpoises were frequently
sighted within several kilometers of the base, mostly to the north or
south of the project area, but occasionally directly across from the
NBKB waterfront on the far side of Toandos Peninsula. Harbor porpoise
presence in the immediate vicinity of the base (i.e., within one
kilometer) remained low. These data were used to generate a density for
Hood Canal. Based on guidance from other line transect surveys
conducted for harbor porpoises using similar monitoring parameters
(e.g., boat speed, number of observers) (Barlow, 1988; Calambokidis et
al., 1993; Carretta et al., 2001), the Navy determined the effective
strip width for the surveys to be one kilometer, or a perpendicular
distance of 500 m from the transect to the left or right of the vessel.
The effective strip width was set at the distance at which the
detection probability for harbor porpoises was equivalent to one, which
assumes that all individuals on a transect are detected. Only sightings
occurring within the effective strip width were used in the density
calculation. By multiplying the trackline length of the surveys by the
effective strip width, the total area surveyed during the surveys was
471.2 km\2\. Thirty-eight individual harbor porpoises were sighted
within this area, resulting in a density of 0.0806 animals/km\2\. To
account for availability bias, or the animals which are unavailable to
be detected because they are submerged, the Navy utilized a g(0) value
of 0.54, derived from other similar line transect surveys (Barlow,
1988; Calambokidis et al., 1993; Carretta et al., 2001). This resulted
in a corrected density of 0.149 animals/km\2\.
Table 5--Number of Potential Incidental Takes of Marine Mammals Within Various Acoustic Threshold Zones
----------------------------------------------------------------------------------------------------------------
Underwater
-------------------------------- Percentage of
Species Density Level B (120 stock
Level A dB) 1 2 abundance
----------------------------------------------------------------------------------------------------------------
California sea lion............................. 71 \3\ 0 568 0.2
Steller sea lion................................ 6 \3\ 0 48 0.1
Harbor seal..................................... 7.93 0 2,056 57
[[Page 22498]]
Killer whale (transient)........................ n/a 0 12 4.9 \4\
Harbor porpoise................................. 0.149 0 40 0.4
----------------------------------------------------------------------------------------------------------------
\1\ The 160-dB acoustic harassment zone associated with impact pile driving would always be subsumed by the 120-
dB harassment zone produced by vibratory driving. Therefore, takes are not calculated separately for the two
zones.
\2\ For species with associated density, density was multiplied by largest ZOI (i.e., 32.4 km). The resulting
value was rounded to the nearest whole number and multiplied by the days of activity. For species with
abundance only, that value was multiplied directly by the days of activity. We assume for reasons described
earlier that no takes would result from airborne noise.
\3\ Figures presented are abundance numbers, not density, and are calculated as the average of average daily
maximum numbers per month, and presented for the month with the highest value. Abundance numbers are rounded
to the nearest whole number for take estimation.
\4\ We assumed that a single pod of six killer whales could be present for as many as two days of the duration,
and that harbor porpoise have the likely potential to be affected by project activities for as many as four
days of the duration.
Analyses and Preliminary Determinations
Negligible Impact Analysis
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . .
an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.'' 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
Level B harassment 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 behavioral
harassment, we consider other factors, such as the likely nature of any
responses (e.g., intensity, duration), the context of any responses
(e.g., critical reproductive time or location, migration), as well as
the number and nature of estimated Level A harassment takes, the number
of estimated mortalities, and effects on habitat.
Pile driving activities associated with the wharf maintenance
project, as outlined 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, from underwater sounds generated from pile driving.
Potential takes could occur if individuals of these species are present
in the ensonified zone when pile driving is happening, which is likely
to occur because (1) harbor seals, which are frequently observed along
the NBKB waterfront, are present within the WRA; (2) sea lions, which
are less frequently observed, transit the WRA en route to haul-outs to
the south at Delta Pier; or (3) cetaceans or pinnipeds transit the
larger Level B harassment zone outside of the WRA.
No injury, serious injury, or mortality is anticipated given the
methods of installation and measures designed to minimize the
possibility of injury to marine mammals. The potential for these
outcomes is minimized through the construction method and duration and
the implementation of the planned mitigation measures. Specifically,
vibratory hammers will be the primary method of installation, and this
activity does not have significant potential to cause injury to marine
mammals due to the relatively low source levels produced (less than 180
dB rms) and the lack of potentially injurious source characteristics.
Impact pile driving produces short, sharp pulses with higher peak
levels and much sharper rise time to reach those peaks. The entire
duration of the specified activity would be eight days; given the
intensity of potential effects as described below, we do not expect
that such a short duration could produce a greater than negligible
impact on the affected stocks.
When impact driving is necessary, required measures (use of a sound
attenuation system, which reduces overall source levels as well as
dampening the sharp, potentially injurious peaks, and implementation of
shutdown zones) significantly reduce any possibility of injury. Given
sufficient ``notice'' through use of soft start, marine mammals are
expected to move away from a sound source that is annoying prior to its
becoming potentially injurious. The likelihood that marine mammal
detection ability by trained observers is high under the environmental
conditions described for Hood Canal further enables the implementation
of shutdowns to avoid injury, serious injury, or mortality.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from past
projects at NBKB, will likely be limited to reactions such as increased
swimming speeds, increased surfacing time, or decreased foraging (if
such activity were occurring). Most likely, individuals will simply
move away from the sound source and be temporarily displaced from the
areas of pile driving, although even this reaction has been observed
primarily only in association with impact pile driving. In response to
vibratory driving, harbor seals (which may be somewhat habituated to
human activity along the NBKB waterfront) have been observed to orient
towards and sometimes move towards the sound. Repeated exposures of
individuals to levels of sound that may cause Level B harassment are
unlikely to result in hearing impairment or to significantly disrupt
foraging behavior. Thus, even repeated Level B harassment of some small
subset of the overall stock is unlikely to result in any significant
realized decrease in fitness to those individuals, and thus would not
result in any adverse impact to the stock as a whole. Level B
harassment will be reduced to the level of least practicable impact
through use of mitigation measures described herein and, if sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the project area while the activity is
occurring.
For pinnipeds, no rookeries are present in the project area, there
are no haul-outs other than those provided opportunistically by man-
made objects, and the project area is not known to provide foraging
habitat of any special importance (other than is afforded by the known
migration of salmonids generally along the Hood Canal shoreline). No
cetaceans are expected within the WRA. The pile driving activities
analyzed here are similar to other nearby construction activities
within the Hood Canal, including recent
[[Page 22499]]
projects conducted by the Navy at the same location as well as work
conducted in 2005 for the Hood Canal Bridge (SR-104) by the Washington
State Department of Transportation, which have taken place with no
reported injuries or mortality to marine mammals, and no known long-
term adverse consequences from behavioral harassment.
In summary, this negligible impact analysis is founded on the
following factors: (1) The possibility of injury, serious injury, or
mortality may reasonably be considered discountable; (2) the
anticipated incidences of Level B harassment consist of, at worst,
temporary (maximum of eight days) modifications in behavior; (3) the
absence of any major rookeries and only a few isolated and
opportunistic haul-out areas near or adjacent to the project site; (4)
the absence of cetaceans within the WRA and generally sporadic
occurrence outside the WRA; (5) the absence of any other known areas or
features of special significance for foraging or reproduction within
the project area; and (6) the presumed efficacy of the planned
mitigation measures in reducing the effects of the specified activity
to the level of least practicable impact. In addition, none of these
stocks are listed under the ESA or designated as depleted under the
MMPA. All of the stocks for which take is authorized are thought to be
increasing or to be within OSP size. In combination, we believe that
these factors, as well as the available body of evidence from other
similar activities, including those conducted at the same time of year
and in the same location, demonstrate that the potential effects of the
specified activity will have only short-term effects on individuals.
The specified activity is not expected to impact rates of recruitment
or survival and will therefore not result in population-level impacts.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, we preliminarily find that the total marine mammal
take from Navy's wharf maintenance activities will have a negligible
impact on the affected marine mammal species or stocks.
Small Numbers Analysis
The numbers of animals authorized to be taken for all stocks (other
than harbor seals) would be considered small relative to the relevant
stocks or populations (ranging from 0.1 to 4.9 percent) even if each
estimated taking occurred to a new individual--an extremely unlikely
scenario. For pinnipeds occurring at the NBKB waterfront, there will
almost certainly be some overlap in individuals present day-to-day.
Further, for the pinniped species, these takes could potentially occur
only within some small portion of the overall regional stock. For
example, of the estimated 296,750 California sea lions, only certain
adult and subadult males--believed to number approximately 3,000-5,000
by Jeffries et al. (2000)--travel north during the non-breeding season.
That number has almost certainly increased with the population of
California sea lions--the 2000 SAR for California sea lions reported an
estimated population size of 204,000-214,000 animals--but likely
remains a relatively small portion of the overall population.
For harbor seals, takes are likely to occur only within some
portion of the population, rather than to animals from the Hood Canal
stock as a whole. As described previously (see ``Description of Marine
Mammals in the Area of the Specified Activity''), established harbor
seal haul-outs are located at such a distance from the project site
that we would not expect the majority of individual animals comprising
the total stock to occur within the affected area, especially over such
a short duration (eight days maximum). Therefore, we expect that the
proposed authorized take level represents repeated exposures of a much
smaller number of individuals in relation to the total stock size.
Further, animals that are resident to Hood Canal, to which any
incidental take would accrue, represent only seven percent of the best
estimate of the larger Washington inland waters harbor seal abundance.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the mitigation and monitoring
measures, we preliminarily find that small numbers of marine mammals
will be taken relative to the populations of the affected species or
stocks.
Impact on Availability of Affected Species for Taking for Subsistence
Uses
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, we have determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
No marine mammal species listed under the ESA are expected to be
affected by these activities. Therefore, we have determined that a
section 7 consultation under the ESA is not required.
National Environmental Policy Act (NEPA)
The Navy prepared an Environmental Assessment (EA) to consider the
direct, indirect and cumulative effects to the human environment
resulting from the wharf maintenance project. NMFS has reviewed the EA
and believes it appropriate to adopt the EA in order to assess the
impacts to the human environment of issuance of an IHA to the Navy and
subsequently sign our own Finding of No Significant Impact (FONSI).
Information in the Navy's application, the Navy's EA, and this notice
collectively provide the environmental information related to proposed
issuance of this IHA for public review and comment. The EA is available
for review at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.
We will review all comments submitted in response to this notice as we
complete the NEPA process, including a final decision of whether to
adopt the Navy's EA and sign a FONSI, prior to a final decision on the
incidental take authorization request.
Proposed Authorization
As a result of these preliminary determinations, we propose to
issue an IHA to the Navy for conducting the described wharf maintenance
activities in the Hood Canal, from July 16, 2015 through January 15,
2016, provided the previously mentioned mitigation, monitoring, and
reporting requirements are incorporated. The proposed IHA language is
provided next.
This section contains a draft of the IHA itself. The wording
contained in this section is proposed for inclusion in the IHA (if
issued).
1. This Incidental Harassment Authorization (IHA) is valid from
July 16, 2015 through January 15, 2016.
2. This IHA is valid only for pile driving and removal activities
associated with maintenance of Explosive Handling Wharf #1 (EHW-1) in
the Hood Canal, Washington.
3. General Conditions
(a) A copy of this IHA must be in the possession of the Navy, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species authorized for taking are the harbor seal (Phoca
vitulina),
[[Page 22500]]
California sea lion (Zalophus californianus), killer whale (transient
only; Orcinus orca), Steller sea lion (Eumetopias jubatus), and the
harbor porpoise (Phocoena phocoena).
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b). See Table 1 (attached) for numbers of
take authorized.
(d) The taking by injury (Level A harassment), serious injury, or
death of any of the species listed in condition 3(b) of the
Authorization or any taking of any other species of marine mammal is
prohibited and may result in the modification, suspension, or
revocation of this IHA.
(e) The Navy shall conduct briefings between construction
supervisors and crews, marine mammal monitoring team, and Navy staff
prior to the start of all pile driving activity, and when new personnel
join the work, in order to explain responsibilities, communication
procedures, marine mammal monitoring protocol, and operational
procedures.
4. Mitigation Measures
In order to ensure the least practicable impact on the species
listed in condition 3(b), the holder of this Authorization is required
to implement the following mitigation measures:
(a) During impact pile driving, the Navy shall implement a minimum
shutdown zone of 10 m radius around the pile, to be effective for all
species of pinniped, and a minimum shutdown zone of 29 m radius around
the pile, to be effective for all species of cetacean. If a marine
mammal comes within the relevant zone, such operations shall cease.
(b) During vibratory pile driving and removal, the Navy shall
implement a minimum shutdown zone of 10 m radius around the pile for
marine mammals. If a marine mammal comes within this zone, such
operations shall cease.
(c) The Navy shall establish monitoring locations as described in
the Marine Mammal Monitoring Plan (Monitoring Plan; attached). For all
pile driving and removal activities, a minimum of three observers shall
be on duty, in addition to a monitoring coordinator. Two of the
observers' primary responsibility shall be to monitor the shutdown
zones, while the additional observer shall be positioned for optimal
monitoring of the surrounding waters within the Waterfront Restricted
Area (WRA). These observers shall record all observations of marine
mammals, regardless of distance from the pile being driven, as well as
behavior and potential behavioral reactions of the animals.
(d) Monitoring shall take place from fifteen minutes prior to
initiation of pile driving activity through thirty minutes post-
completion of pile driving activity. Pre-activity monitoring shall be
conducted for fifteen minutes to ensure that the shutdown zone is clear
of marine mammals, and pile driving may commence when observers have
declared the shutdown zone clear of marine mammals. In the event of a
delay or shutdown of activity resulting from marine mammals in the
shutdown zone, animals shall be allowed to remain in the shutdown zone
(i.e., must leave of their own volition) and their behavior shall be
monitored and documented. Monitoring shall occur throughout the time
required to drive a pile. The shutdown zone must be determined to be
clear during periods of good visibility (i.e., the entire shutdown zone
and surrounding waters within the WRA must be visible to the naked
eye).
(e) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted (i.e.,
implementation of shutdown at one pile driving location may not
necessarily trigger shutdown at other locations when pile driving is
occurring concurrently). If pile driving is halted or delayed at a
specific location due to the presence of a marine mammal, the activity
may not commence or resume until either the animal has voluntarily left
and been visually confirmed beyond the shutdown zone or fifteen minutes
have passed without re-detection of the animal.
(f) Monitoring shall be conducted by qualified observers, as
described in the Monitoring Plan. Trained observers shall be placed
from the best vantage point(s) practicable (i.e., provides the most
unobstructed view of the monitoring zones and are at the highest
elevation possible) to monitor for marine mammals and implement
shutdown or delay procedures when applicable through communication with
the equipment operator.
(g) Approved sound attenuation devices shall be used during impact
pile driving operations. The Navy shall implement the necessary
contractual requirements to ensure that such devices are capable of
achieving optimal performance, and that deployment of the device is
implemented properly such that no reduction in performance may be
attributable to faulty deployment.
(h) The Navy shall use soft start techniques recommended by NMFS
for vibratory and impact pile driving. Soft start for vibratory drivers
requires contractors to initiate sound for fifteen seconds at reduced
energy followed by a thirty-second waiting period. This procedure is
repeated two additional times. Soft start for impact drivers requires
contractors to provide an initial set of strikes at reduced energy,
followed by a thirty-second waiting period, then two subsequent reduced
energy strike sets. Soft start shall be implemented at the start of
each day's pile driving and at any time following cessation of pile
driving for a period of thirty minutes or longer. Soft start for impact
drivers must be implemented at any time following cessation of impact
driving for a period of thirty minutes or longer. The Navy may
discontinue use of vibratory soft starts if unsafe working conditions
believed to result from implementation of the measure are reported by
the contractor, verified by an independent safety inspection, and
reported to NMFS.
(i) Pile driving shall only be conducted during daylight hours and
when the entire shutdown zone is visible.
5. Monitoring
The holder of this Authorization is required to conduct marine
mammal monitoring during pile driving activity. Marine mammal
monitoring and reporting shall be conducted in accordance with the
Monitoring Plan.
(a) The Navy shall collect sighting data and behavioral responses
to pile driving for marine mammal species observed in the region of
activity during the period of activity. All observers shall be trained
in marine mammal identification and behaviors, and shall have no other
construction related tasks while conducting monitoring.
(b) For all marine mammal monitoring, the information shall be
recorded as described in the Monitoring Plan.
6. Reporting
The holder of this Authorization is required to:
(a) Submit a draft report on all marine mammal monitoring conducted
under the IHA within ninety calendar days of the end of the in-water
work period. A final report shall be prepared and submitted within
thirty days following resolution of comments on the draft report from
NMFS. This report must contain the informational elements described in
the Monitoring Plan, at minimum (see attached).
(b) Reporting injured or dead marine mammals:
i. In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this IHA
(as determined by the lead observer), such as an injury (Level A
harassment), serious injury, or
[[Page 22501]]
mortality, Navy shall immediately cease the specified activities and
report the incident to the Office of Protected Resources (301-427-
8425), NMFS, and the West Coast Regional Stranding Coordinator (206-
526-6550), NMFS. The report must include the following information:
A. Time and date of the incident;
B. Description of the incident;
C. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
D. Description of all marine mammal observations in the 24 hours
preceding the incident;
E. Species identification or description of the animal(s) involved;
F. Fate of the animal(s); and
G. Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with Navy to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. Navy may not resume
their activities until notified by NMFS.
i. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), Navy shall immediately report
the incident to the Office of Protected Resources, NMFS, and the West
Coast Regional Stranding Coordinator, NMFS.
The report must include the same information identified in 6(b)(i)
of this IHA. Activities may continue while NMFS reviews the
circumstances of the incident and makes a final determination on the
cause of the reported injury or death. NMFS will work with Navy to
determine whether additional mitigation measures or modifications to
the activities are appropriate.
ii. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, scavenger damage), Navy shall report the incident to the
Office of Protected Resources, NMFS, and the West Coast Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. Navy
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS. The cause of injury or death may
be subject to review and a final determination by NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
the authorized taking is having more than a negligible impact on the
species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analysis, the draft authorization, and
any other aspect of this Notice of Proposed IHA for Navy's wharf
maintenance activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on Navy's request for an MMPA authorization.
Dated: April 16, 2015.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2015-09253 Filed 4-21-15; 8:45 am]
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