[Federal Register Volume 84, Number 166 (Tuesday, August 27, 2019)]
[Notices]
[Pages 44866-44884]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-18351]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XG908
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the King Pile Markers Project on
the Columbia River
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from U.S. Army Corps of Engineers,
Portland District (Corps) for authorization to take marine mammals
incidental to the King Pile Markers Project on the Columbia River in
Washington and Oregon Pursuant to the Marine Mammal Protection Act
(MMPA). NMFS is requesting comments on its proposal to issue an
incidental harassment authorization (IHA) to incidentally take marine
mammals during the specified activities. NMFS is also requesting
comments on a possible one-year renewal that could be issued under
certain circumstances and if all requirements are met, as described in
Request for Public Comments at the end of this notice. NMFS will
consider public comments prior to making any final decision on the
issuance of the requested MMPA authorizations and agency responses will
be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than
September 26, 2019.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or
[[Page 44867]]
received after the end of the comment period. Comments received
electronically, including all attachments, must not exceed a 25-
megabyte file size. Attachments to electronic comments will be accepted
in Microsoft Word or Excel or Adobe PDF file formats only. All comments
received are a part of the public record and will generally be posted
online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All
personal identifying information (e.g., name, address) voluntarily
submitted by the commenter may be publicly accessible. Do not submit
confidential business information or otherwise sensitive or protected
information.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth.
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has preliminarily determined that the
issuance of the proposed IHA qualifies to be categorically excluded
from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On February 11, 2019, NMFS received a request from the Corps for an
IHA to take marine mammals incidental to pile driving associated with
the replacement of king pile markers at numerous dike locations in the
lower Columbia River system. The king pile markers are located in
Oregon and Washington between river miles (RM) 41 and 137. The
application was deemed adequate and complete on August 2, 2019. The
Corps' request is for take of small numbers of harbor seal (Phoca
viutlina), Steller sea lion (Eumetopias jubatus), and California sea
lion (Zalophus californianus) that may occur in the vicinity of the
project by Level B harassment. Neither the Corps nor NMFS expects
serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
The Corps is proposing to replace up to 68 king pile markers at 68
pile dike sites along the lower Columbia River between river miles (RM)
41 and 137 (see Figure 1). There are a total of 256 pile dikes, in the
existing dike system. The king piles that require replacement are not
functioning as intended. They were designed to aid navigation by
helping mariners avoid pile dikes during high water. Many exiting king
piles are either missing completely, damaged, or degraded to a point
where they no longer provide a visual identifier. This lack of
visibility poses a safety concern to both recreational and commercial
boaters on the river. Replacement of the king piles will improve
visibility of pile dikes and improve safety for Columbia River traffic.
Impact and vibratory pile installation would introduce underwater
sounds at levels that may result in take, by Level B harassment, of
marine mammals in the lower Columbia River. Construction activities are
expected to last 61 days.
Dates and Duration
Pile installation would be done during the 2019 in-water work
window of October 1, 2019 to November 30, 2019. Impact driving will
only take place in November, as per NMFS 2012 SLOPES IV programmatic
biological opinion. Since the in-water work window is approximately 61
days and pile installation activity could potentially occur on each day
of that window, it is estimated that the project could require up to 61
days. Pile installation will be conducted during standard daylight
working hours. Up to one hour of impact driving and 30 minutes of
vibratory driving could occur at each pile dike location per day.
Specific Geographic Region
Pile dikes are located in both Oregon and Washington on the
Columbia River between RM 41 and 137. The project area is dominated by
freshwater inputs from the Columbia and Willamette rivers. The Mouth of
the Columbia River designated at RM 0 while the Bonneville Dam is
located at RM 146. The existing depth (relative to Columbia River low
water datum) at the locations of missing king pile markers varies from
less than 10 ft. to greater than 30 ft., but is generally in the 20-30
foot range, possibly indicating scour protection rock thicknesses of up
to 10 feet.
BILLING CODE 3510-22-P
[[Page 44868]]
[GRAPHIC] [TIFF OMITTED] TN27AU19.000
BILLING CODE 3510-22-C
Detailed Description of Specific Activity
King pile markers consist of one or more tall piles (up to about 20
feet above the Columbia River mean low water (MLW) datum) marking the
end of a pile dike for navigational safety. King piles were originally
constructed as part of a cluster of piles called an outer dolphin.
Columbia River pile dikes are permeable groins extending into the river
and consist of two or three rows of vertical untreated timber pilings
driven in staggered rows of 5-foot centers alternately placed on each
side of horizontal spreader piles and fastened together. Rock placed at
the base of the piles and at the shore connection help protect against
scour.
Construction will consist of driving new replacement piles, and
adding scour protection rock around new piles as needed. Each
replacement king pile marker will consist of a single steel pipe pile
of up to 24-inch diameter. Piles will be driven up to 30-35 feet of
embedment. If piles cannot be driven through the existing scour
protection rock, the marker will be offset. Scour protection rock (less
than 25 cubic yards) may be placed around the base of any offset piles.
The total estimated
[[Page 44869]]
quantity of piles needed for this project is 68 piles.
Barges will transport all materials (new piles, and scour
protection rock) to and from the site and serve as staging platforms
during construction. Barges will be moved by tugboats, then spudded or
anchored into position.
At each king pile marker, piles will be installed using vibratory
drivers (e.g., APE Model 200 vibratory driver or equivalent) and/or
impact hammers (D-46-42 diesel impact hammer or equivalent) operated
from a barge-mounted crane. Vibratory driving is the preferred method;
however, impact driving may be necessary if piles cannot be driven to
the necessary embedment depth using the vibratory method. Under the
Standard Local Operating Procedures for Endangered Species (SLOPES) IV
biological opinion (NMFS 2012a), impact driving in the Columbia River
is only allowed during the month of November, and must use an acoustic
attenuation device (e.g., a bubble curtain). This programmatic
biological opinion examined the effects of implementing standard local
operating procedures for Corps activities involving inwater or over-
water structures (including pile driving, access management, and minor
discharges) in Oregon and the south shore of the Columbia River and its
tributaries. The measures described above are required to protect 17
fish species, including multiple salmon species (Oncorhynchus sp) as
well as Southern green sturgeon (Acipenser medirostris) and eulachon
(Thaleichthys pacificus). Note that the programmatic biological opinion
does not apply to this proposed IHA, but rather to the Corps' pile
driving activities. Piles are generally installed by a rig that
supports the pile leads, raises the pile, and operates a driver.
Driving shoes may be used.
It is estimated that each pile will take up to one hour to install
using vibratory methods with 30 minutes of that time being actual
driving of the pile. Whether impact or vibratory methods are employed,
one pile will be installed per pile dike location per day. Depending on
weather and other logistical constraints, piles will be installed at up
to 9 locations per day. For piles driven with an impact hammer, there
are an estimated 550 strikes per pile requiring up to one hour,
assuming a hammer energy rating of 55,000 ft-lbs and piles being driven
through a combination of sand and rock (Bainbridge Island Ferry
Terminal, WSDOT 2018a, 2018b). Actual pile driving rates will vary, and
a typical day will likely involve fewer locations and fewer strikes.
The contractor may use multiple pile-driving and material barges to
facilitate completion of work within the in-water work window. However,
concurrent work at two or more locations are unlikely to be in close
proximity to each other.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all marine mammal species with expected potential for
occurrence in the lower Columbia River and summarizes information
related to the population or stock, including regulatory status under
the MMPA and ESA and potential biological removal (PBR), where known.
For taxonomy, we follow Committee on Taxonomy (2016). PBR is defined by
the MMPA as the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while
allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprise that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's 2018 U.S. Pacific Marine Mammal SARs (Carretta et al., 2019).
All values presented in Table 1 are the most recent available at the
time of publication and are available in the 2018 SARs (Carretta et
al., 2019).
Table 1--Marine Mammal Species Likely To Be in Lower Columbia River Near King Pile Marker Sites
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S. Stock............. -, -, N 257,606 (N/A, 233,515, 14,011 >320
2014).
Steller sea lion................ Eumetopias jubatus..... Eastern U.S............ -, -, N 41,638 (See SAR, 2,498 108
41,638, 2015).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina Oregon and Washington -, -, N UNK (UNK, UNK, 1999).. UND 10.6
richardii. Coast.
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance. In some cases, CV is not applicable.
[[Page 44870]]
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
All species that could potentially occur in the proposed survey
areas are included in Table 1. All three species (with three managed
stocks) described below co-occur temporally and spatially co-occur with
the proposed activity to the degree that take is reasonably likely to
occur, and we have proposed authorizing it.
California Sea Lion
California sea lions are found along the west coast from the
southern tip of Baja California to southeast Alaska. They breed mainly
on offshore islands from Southern California's Channel Islands south to
Mexico. Non-breeding males often roam north in spring foraging for
food. Since the mid-1980s, increasing numbers of California sea lions
have been documented feeding on fish along the Washington coast and--
more recently--in the Columbia River as far upstream as Bonneville Dam,
145 mi (233 km) from the river mouth. Large numbers of California sea
lions also use the South Jetty at the Mouth of Columbia River for
hauling out (Jeffries 2000). The jetty is located approximately 40
miles downriver from the nearest king pile that would be replaced.
Oregon Department of Fish and Wildlife survey information (2007 and
2014) indicates that California sea lions are relatively less prevalent
in the Pacific Northwest during June and July, though in the months
just before and after their absence there can be several hundred using
the South Jetty. More frequent Washington Department of Fish and
Wildlife surveys (2014) indicate greater numbers in the summer, and use
remains concentrated to fall and winter months. Nearly all California
sea lions in the Pacific Northwest are sub-adult and adult males
(females and young generally stay in California).
Although coast wide the population has grown, the numbers seen in
the river and upstream at Bonneville dam during both the spring and
fall/winter observation periods have decreased since 2003. This may be
in due to the California sea lion management activities that have been
implemented to reduce their predation rates on salmon and steelhead.
These activities include hazing of all California sea lions near the
dam and fish ladders, as well as the lethal removal of the individuals
with the highest predation rates (Tidwell et al. 2019).
Steller Sea Lion
The range of the Steller sea lion includes the North Pacific Ocean
rim from California to northern Japan. Steller sea lions forage in
nearshore and pelagic waters where they are opportunistic predators.
Steller sea lion populations that primarily occur east of 144[deg] W
(Cape Suckling, Alaska) comprise the Eastern Distinct Population
Segment (DPS) (Carretta et al. 2019). Stellar sea lions (Eumetopias
jubatus) are currently the most common marine mammal observed in the
proposed action area. They are frequently observed between the river's
mouth (RM 0) and the Bonneville Dam tailrace (RM 146). Large numbers of
Steller sea lions use the South Jetty for hauling out (Jeffries 2000)
and are present, in varying abundances, all year.
During an August-December monitoring period the number of
individuals observed at Bonneville Dam has been increasing for the past
decade (Tidwell et al. 2019). The Bonneville dam observation area is
approximately 10 miles upstream of the nearest king pile that is
proposed for replacement under this IHA.
Harbor Seal
Harbor seals range from Baja California, north along the western
coasts of the United States, British Columbia and southeast Alaska,
west through the Gulf of Alaska, Prince William Sound, and the Aleutian
Islands, and north in the Bering Sea to Cape Newenham and the Pribilof
Islands. They are one of the most abundant pinnipeds in Oregon and can
typically be found in coastal marine and estuarine waters of the Oregon
coast throughout the year. On land, they can be found on offshore rocks
and islands, along shore, and on exposed flats in the estuary (Harvey
1987). They haul out on rocks, reefs, beaches, and drifting glacial ice
and feed in marine, estuarine, and occasionally fresh waters. Harbor
seals generally are non-migratory, with local movements associated with
tides, weather, season, food availability, and reproduction. Harbor
seals do not make extensive pelagic migrations (Carretta et al. 2019).
Major haul-out sites with more than 500 individuals have been noted in
the Columbia River and are downstream of Tongue Point, about 25 miles
downstream of the nearest king pile driving location proposed for this
project (Jeffries 2000). They are uncommon upstream near the Bonneville
dam in all seasons.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 2.
Table 2--Marine Mammal Hearing Groups
[NMFS, 2018]
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Hearing group Generalized hearing range *
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Low-frequency (LF) cetaceans (baleen whales)........... 7 Hz to 35 kHz.
[[Page 44871]]
Mid-frequency (MF) cetaceans (dolphins, toothed whales, 150 Hz to 160 kHz.
beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises, Kogia, 275 Hz to 160 kHz.
river dolphins, cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals)........ 50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions and fur 60 Hz to 39 kHz.
seals).
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* Represents the generalized hearing range for the entire group as a composite (i.e., all species within the
group), where individual species' hearing ranges are typically not as broad. Generalized hearing range chosen
based on ~65 dB threshold from normalized composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Three pinniped species (two otariid and one phocid) have the reasonable
potential to co-occur with the proposed survey activities. Please refer
to Table 2
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
Acoustic effects on marine mammals during the specified activity
can occur from vibratory and impact pile driving. The effects of
underwater noise from the Corps' proposed activities have the potential
to result in Level A and Level B harassment of marine mammals in the
vicinity of the project area.
Description of Sound Sources
This section contains a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used in this
proposal inasmuch as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document. For general
information on sound and its interaction with the marine environment,
please see, e.g., Au and Hastings (2008); Richardson et al. (1995);
Urick (1983).
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 or corresponding points of a sound wave
(length of one cycle). Higher frequency sounds have shorter wavelengths
than lower frequency sounds, and typically attenuate (decrease) more
rapidly, except in certain cases in shallower water. Amplitude is the
height of the sound pressure wave or the ``loudness'' of a sound and is
typically described using the relative unit of the dB. A sound pressure
level (SPL) in dB is described as the ratio between a measured pressure
and a reference pressure (for underwater sound, this is 1 microPascal
([mu]Pa)), and is a logarithmic unit that accounts for large variations
in amplitude; therefore, a relatively small change in dB corresponds to
large changes in sound pressure. The source level (SL) represents the
SPL referenced at a distance of 1 m from the source (referenced to 1
[mu]Pa), while the received level is the SPL at the listener's position
(referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square 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.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy in a stated frequency band over a stated
time interval or event, and considers both intensity and duration of
exposure. The per-pulse SEL is calculated over the time window
containing the entire pulse (i.e., 100 percent of the acoustic energy).
SEL is a cumulative metric; it can be accumulated over a single pulse,
or calculated over periods containing multiple pulses. Cumulative SEL
represents the total energy accumulated by a receiver over a defined
time window or during an event. Peak sound pressure (also referred to
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous
sound pressure measurable in the water at a specified distance from the
source, and is represented in the same units as the rms sound pressure.
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 a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for sound produced by the
pile driving activity considered here. 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, which is
defined as environmental background sound levels lacking a single
source or point (Richardson et al., 1995). The sound
[[Page 44872]]
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., wind and waves, earthquakes, ice, atmospheric sound),
biological (e.g., sounds produced by marine mammals, fish, and
invertebrates), and anthropogenic (e.g., vessels, dredging,
construction) sound. A number of sources contribute to ambient sound,
including wind and waves, which are a main source of naturally
occurring ambient sound for frequencies between 200 Hz and 50 kilohertz
(kHz) (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Precipitation can become an
important component of total sound at frequencies above 500 Hz, and
possibly down to 100 Hz during quiet times. Marine mammals can
contribute significantly to ambient sound levels, as can some fish and
snapping shrimp. The frequency band for biological contributions is
from approximately 12 Hz to over 100 kHz. Sources of ambient sound
related to human activity include transportation (surface vessels),
dredging and construction, oil and gas drilling and production,
geophysical surveys, sonar, and explosions. Vessel noise typically
dominates the total ambient sound 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.
The sum of the various natural and anthropogenic sound sources that
comprise ambient sound at any given location and time depends not only
on the source levels (as determined by current weather conditions and
levels of biological and human 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.
Sounds are often considered to fall into one of two general 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.
The distinction between these two sound types is not always obvious, as
certain signals share properties of both pulsed and non-pulsed sounds.
A signal near a source could be categorized as a pulse, but due to
propagation effects as it moves farther from the source, the signal
duration becomes longer (e.g., Greene and Richardson, 1988).
Pulsed sound sources (e.g., airguns, 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, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or intermittent (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. The
duration of such sounds, as received at a distance, can be greatly
extended in a highly reverberant environment.
The impulsive sound generated by impact hammers is characterized by
rapid rise times and high peak levels. Vibratory hammers produce non-
impulsive, continuous noise at levels significantly lower than those
produced by impact hammers. Rise time is slower, reducing the
probability and severity of injury, and sound energy is distributed
over a greater amount of time (e.g., Nedwell and Edwards, 2002; Carlson
et al., 2005).
Acoustic Effects on Marine Mammals
We previously provided general background information on marine
mammal hearing (see ``Description of Marine Mammals in the Area of the
Specified Activity''). Here, we discuss the potential effects of sound
on marine mammals.
Note that, in the following discussion, we refer in many cases to a
review article concerning studies of noise-induced hearing loss
conducted from 1996-2015 (i.e., Finneran, 2015). For study-specific
citations, please see that work. Anthropogenic sounds cover a broad
range of frequencies and sound levels and can have a range of highly
variable impacts on marine life, from none or minor to potentially
severe responses, depending on received levels, duration of exposure,
behavioral context, and various other factors. The potential effects of
underwater sound from active acoustic sources can potentially result in
one or more of the following: Temporary or permanent hearing
impairment, non-auditory physical or physiological effects, behavioral
disturbance, stress, and masking (Richardson et al., 1995; Gordon et
al., 2004; Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et
al., 2009). The degree of effect is intrinsically related to the signal
characteristics, received level, distance from the source, and duration
of the sound exposure. In general, sudden, high level sounds can cause
hearing loss, as can longer exposures to lower level sounds. Temporary
or permanent loss of hearing will occur almost exclusively for noise
within an animal's hearing range. We first describe specific
manifestations of acoustic effects before providing discussion specific
to pile driving activities.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the
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masking zone may be highly variable in size.
We describe the more severe effects (i.e., certain non-auditory
physical or physiological effects) only briefly as we do not expect
that there is a reasonable likelihood that pile driving may result in
such effects (see below for further discussion). Potential effects from
explosive 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). Non-auditory
physiological effects or injuries that theoretically might occur in
marine mammals exposed to high level underwater sound or as a secondary
effect of extreme behavioral reactions (e.g., change in dive profile as
a result of an avoidance reaction) caused by exposure to sound include
neurological effects, bubble formation, resonance effects, and other
types of organ or tissue damage (Cox et al., 2006; Southall et al.,
2007; Zimmer and Tyack, 2007). The construction activities considered
here do not involve the use of devices such as explosives or mid-
frequency tactical sonar that are associated with these types of
effects.
Threshold Shift--Marine mammals exposed to high-intensity sound, or
to lower-intensity sound for prolonged periods, can experience hearing
threshold shift (TS), which is the loss of hearing sensitivity at
certain frequency ranges (Finneran, 2015). TS can be permanent (PTS),
in which case the loss of hearing sensitivity is not fully recoverable,
or temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Repeated sound exposure that
leads to TTS could cause PTS. In severe cases of PTS, there can be
total or partial deafness, while in most cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above (a 40-dB threshold shift approximates PTS onset;
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB
threshold shift approximates TTS onset; e.g., Southall et al. 2007).
Based on data from terrestrial mammals, a precautionary assumption is
that the PTS thresholds for impulse sounds (such as impact pile driving
pulses as received close to the source) are at least 6 dB higher than
the TTS threshold on a peak-pressure basis and PTS cumulative sound
exposure level thresholds are 15 to 20 dB higher than TTS cumulative
sound exposure level thresholds (Southall et al., 2007). Given the
higher level of sound or longer exposure duration necessary to cause
PTS as compared with TTS, it is considerably less likely that PTS could
occur.
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. Few data
on sound levels and durations necessary to elicit mild TTS have been
obtained for marine mammals.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that occurs during a time where ambient noise is lower and there
are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and three species of pinnipeds (northern elephant
seal, harbor seal, and California sea lion) exposed to a limited number
of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). Additionally, the existing marine mammal TTS data
come from a limited number of individuals within these species. There
are no data available on noise-induced hearing loss for mysticetes. For
summaries of data on TTS in marine mammals or for further discussion of
TTS onset thresholds, please see Southall et al. (2007), Finneran and
Jenkins (2012), Finneran (2015), and NMFS (2018).
Behavioral Effects--Behavioral disturbance may include a variety of
effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Behavioral responses to sound are highly
variable and context-specific and any reactions depend on numerous
intrinsic and extrinsic factors (e.g., species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day), as well as the interplay between factors (e.g.,
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007;
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not
only among individuals but also within an individual, depending on
previous experience with a sound source, context, and numerous other
factors (Ellison et al., 2012), and can vary depending on
characteristics associated with the sound source (e.g., whether it is
moving or stationary, number of sources, distance from the source).
Please see Appendices B-C of Southall et al. (2007) for a review of
studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to
[[Page 44874]]
stimuli that are perceived as neither aversive nor beneficial,'' rather
than as, more generally, moderation in response to human disturbance
(Bejder et al., 2009). The opposite process is sensitization, when an
unpleasant experience leads to subsequent responses, often in the form
of avoidance, at a lower level of exposure. As noted, behavioral state
may affect the type of response. For example, animals that are resting
may show greater behavioral change in response to disturbing sound
levels than animals that are highly motivated to remain in an area for
feeding (Richardson et al., 1995; NRC, 2003; Wartzok et al., 2003).
Controlled experiments with captive marine mammals have showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources
(typically airguns or acoustic harassment devices) have been varied but
often consist of avoidance behavior or other behavioral changes
suggesting discomfort (Morton and Symonds, 2002; see also Richardson et
al., 1995; Nowacek et al., 2007). However, many delphinids approach
low-frequency airgun source vessels with no apparent discomfort or
obvious behavioral change (e.g., Barkaszi et al., 2012), indicating the
importance of frequency output in relation to the species' hearing
sensitivity.
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et
al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from airgun surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other
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critical behaviors such as foraging or resting). These effects have
generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996). However, Ridgway et al. (2006)
reported that increased vigilance in bottlenose dolphins exposed to
sound over a five-day period did not cause any sleep deprivation or
stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher intensity, and may occur whether the sound is natural (e.g.,
snapping shrimp, wind, waves, precipitation) or anthropogenic (e.g.,
shipping, sonar, seismic exploration) in origin. The ability of a noise
source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009;).
Masking can be reduced in situations where the signal and noise come
from different directions (Richardson et al., 1995), through amplitude
modulation of the signal, or through other compensatory behaviors
(Houser and Moore, 2014). Masking can be tested directly in captive
species (e.g., Erbe, 2008), but in wild populations it must
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be either modeled or inferred from evidence of masking compensation.
There are few studies addressing real-world masking sounds likely to be
experienced by marine mammals in the wild (e.g., Branstetter et al.,
2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
that have the potential to cause behavioral harassment, depending on
their distance from pile driving activities. Airborne noise would
primarily be an issue for pinnipeds that are swimming near the project
site within the range of noise levels elevated above the acoustic
criteria. We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
previously have been `taken' because 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. Therefore, we do not believe that authorization of
incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further here.
Potential Effects of the Corps' Proposed Activity--As described
previously (see ``Description of Active Acoustic Sound Sources''), the
Corps proposes to conduct impact and vibratory driving. 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. With both types, it is likely that the pile driving
could result in temporary, short term changes in an animal's typical
behavioral patterns and/or avoidance of the affected area. These
behavioral changes may include (Richardson et al., 1995): Changing
durations of surfacing and dives; 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; avoidance of areas where sound sources
are located; and/or flight responses.
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 lead to effects on growth,
survival, or reproduction, such as drastic changes in diving/surfacing
patterns or significant habitat abandonment are extremely unlikely in
this area (i.e., relatively shallow waters in an area with considerable
vessel traffic).
Whether impact or vibratory driving, sound sources would be active
for relatively short durations, with relation to potential for masking.
The frequencies output by pile driving activity are lower than those
used by most species expected to be regularly present for communication
or foraging. We expect insignificant impacts from masking, and 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.
Anticipated Effects on Marine Mammal Habitat
The proposed activities may have potential short-term impacts to
food sources such as forage fish. The proposed activities could also
affect acoustic habitat (see masking discussion above), but meaningful
impacts are unlikely. There are no known foraging hotspots, or other
ocean bottom structures of significant biological importance to marine
mammals present in the waters in the vicinity of the multiple king pile
marker sites. Therefore, the main impact issue associated with the
proposed activity would be temporarily elevated sound levels and the
associated direct effects on marine mammals, as discussed previously.
The most likely impact to marine mammal habitat occurs from pile
driving effects on likely marine mammal prey (i.e., fish) near where
the piles are installed. Impacts to the immediate substrate during
installation of piles would be minor since piles would be driven
through existing enrockment structures. This could result in limited,
temporary suspension of sediments, which could impact water quality and
visibility for a short amount of time, but which would not be expected
to have any effects on individual marine mammals. Impacts to substrate
are therefore not discussed further.
Effects to Prey--Sound may affect marine mammals through impacts on
the abundance, behavior, or distribution of prey species (e.g.,
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies
by species, season, and location and, for some, is not well documented.
Here, we describe studies regarding the effects of noise on known
marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation
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(e.g., feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, although several are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fish from pile driving activities at the
project areas would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the expected
short daily duration of individual pile driving events at each king
pile marker location and the relatively small areas being affected.
In summary, given the short duration of sound (up to 90 minutes)
associated with individual pile driving events and the small area being
affected relative to available nearby habitat, 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 or
other prey. Thus, we conclude that impacts of the specified activity
are not likely to have more than short-term adverse effects on any prey
habitat or populations of prey species. Further, any impacts to marine
mammal habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
The area impacted by the project is relatively small compared to
the available habitat in the lower Columbia River and Columbia River
estuary. Any behavioral avoidance by fish of the disturbed area would
still leave significantly large areas of fish and marine mammal
foraging habitat in the nearby vicinity. As described in the preceding,
the potential for the Corps' construction to affect the availability of
prey to marine mammals or to meaningfully impact the quality of
physical or acoustic habitat is considered to be insignificant.
Furthermore, impact driving will only take place in November, as per
the 2012 SLOPES IV programmatic biological opinion to protect 17 fish
species, including multiple salmon species. Effects to habitat will not
be discussed further in this document.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to pile driving. Based on the nature of the
activity and the anticipated effectiveness of the mitigation measures
(i.e., use of bubble curtains during impact driving, establishment of
shutdown zones--discussed in detail below in Proposed Mitigation
section, Level A harassment is neither anticipated nor proposed to be
authorized.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the proposed take
estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g.,
vibratory pile-
[[Page 44878]]
driving, drilling) and above 160 dB re 1 [mu]Pa (rms) for non-explosive
impulsive (e.g., seismic airguns) or intermittent (e.g., scientific
sonar) sources.
The Corps' proposed activity includes the use of continuous
(vibratory pile driving) and impulsive (impact pile driving) sources,
and therefore the 120 and 160 dB re 1 [mu]Pa (rms) are applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The Corp's proposed activity includes the
use of impulsive (impact pile driving) and non-impulsive (vibratory
pile driving) source.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS 2018 Technical Guidance, which may be accessed at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
Sound Propagation
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * log10 (R1/R2),
Where:
B = transmission loss coefficient (assumed to be 15)
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)).
As is common practice in coastal waters, here we assume practical
spreading loss (4.5 dB reduction in sound level for each doubling of
distance). Practical spreading is a compromise that is often used under
conditions where water depth increases as the receiver moves away from
the shoreline, resulting in an expected propagation environment that
would lie between spherical and cylindrical spreading loss conditions.
Sound Source Levels
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. Pile driving may be done
with either vibratory or impact hammer, with vibratory driving being
the preferred method. Due to anticipated enrockment surrounding
existing piles, however, use of impact hammers may be required.
Estimated in-water sound levels anticipated from vibratory
installation and impact hammer installation of steel pipe piles are
summarized in Table 4. Sound pressure levels for impact driving of 24-
in steel piles were taken from Caltrans (2015). The SLs in the table
below include a 7 dB reduction for impact driving due to attenuation
associated with the use of bubble curtains. Vibratory driving source
levels for 24-in steel piles came from the United States Navy (2015).
Due to the short operating window (61 days), and concerns about
possible delays due to bad weather, the Corps does not propose to use
bubble curtains during vibratory driving. This should expedite pile
installation at king pile locations where use of vibratory hammers is
employed.
[[Page 44879]]
Table 4--Estimated Underwater Source Levels Associated With Vibratory Pile Driving and Impact Hammer Pile
Driving
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Pile type Sound Pressure Level (SPL) (single strike)
----------------------------------------------------------------------------------------------------------------
24-Inch Steel Pipe Piles w/ 200 dBPEAK................ 187 dBRMS................. 171 dBSEL.
impact hammer (attenuated) \1\.
24-Inch Steel Pipe Piles w/ Not Available............. 161 dBRMS................. Not Available.
vibratory (unattenuated) \2\.
----------------------------------------------------------------------------------------------------------------
\1\ From Caltrans (2015) Acoustic data from CalTrans 2015 Table I.2-1. Summary of Near-Source (10-Meter)
Unattenuated Sound Pressure Levels for In-Water Pile Driving Using an Impact Hammer: 0.61-meter (24-inch)
steel pipe pile in water ~15 meters deep, w/7dB reduction for use of attenuation (as per NMFS 2019 pers.
Comm).
\2\ From United States Navy. 2015. Proxy source sound levels and potential bubble curtain attenuation for
acoustic modeling of nearshore marine pile driving at Navy installations in Puget Sound. Prepared by Michael
Slater, Naval Surface Warfare Center, Carderock Division, and Sharon Rainsberry, Naval Facilities Engineering
Command Northwest. Revised January 2015. Table 2-2.
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources such as pile
driving, NMFS User Spreadsheet predicts the distance at which, if a
marine mammal remained at that distance the whole duration of the
activity, it would incur PTS. Inputs used in the User Spreadsheet, and
the resulting Level A harassment isopleths are reported below in Tables
5 and 6 respectively. Note that while up to 9 piles could be installed
in a single day, they would be driven at different locations and the
ensonified areas associated with each location would not overlap. For
the purpose of calculating PTS isopleths using the User Spreadsheet, it
is assumed that a single pile would be driven per day at a single
location (i.e., the zones for each pile are calculated independently)
since there will be no overlap of disturbance zones from adjacent king
pile installation sites. The Level B harassment isopleths were
calculated using the practical spreading loss model. Underwater noise
will fall below the behavioral effects threshold of 160 dB for impact
driving and 120 dB rms for vibratory driving at the distances shown in
Table 6.
Table 5--NMFS Technical Guidance (2018) User Spreadsheet Input To
Calculate PTS Isopleths
------------------------------------------------------------------------
24-in Steel
Inputs 24-in Steel impact vibratory
installation installation
------------------------------------------------------------------------
Spreadsheet Tab Used............ (E.1) Impact Pile (A.1) Vibratory
Driving. Pile Driving.
Source Level (Single Strike/shot 171 dB SEL/200 dB 161 dB RMS.
SEL). Peak.
Weighting Factor Adjustment 2................. 2.5.
(kHz).
Number of strikes per pile...... 550...............
Number of piles per day......... 1................. 1.
Duration to install single pile 60................ 30.
(minutes).
Propagation (xLogR)............. 15................ 15.
Distance of source level 10................ 10.
measurement (meters) +.
------------------------------------------------------------------------
Table 6--Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Level A harassment Level B harassment
--------------------------------------------------------------
Permanent Threshold Shift (PTS) Isopleth (meters)
Noise generation type isopleth (meters) ----------------------
----------------------------------------
Phocid pinniped Otariid pinniped All groups
----------------------------------------------------------------------------------------------------------------
24'' Steel Pipe Impact attenuated................ 56.9 4.1 631
24'' Steel Pipe Vibratory unattenuated........... 2.6 0.2 5,412
----------------------------------------------------------------------------------------------------------------
The Corps and NMFS do not anticipate take of marine mammals by
Level A harassment due to the relatively small PTS isopleths as well as
required shutdown if an animal approaches the zone. The Level B
harassment zone area for each king pile site will differ since the
landforms and river morphology are unique to each king pile location.
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations. Pinnipeds are typically concentrated at haul out sites
(e.g., the MCR South jetty) and feeding areas where there are
concentrations of salmon (e.g., Bonneville Dam). Individual animals
that occur near king pile locations are likely to be in transit between
these two prominent sites. Pinnipeds that travel to Bonneville Dam
consistently forage in all three of the dam's tailraces. A tailrace is
the flume, or water channel leading away from the dam. Pinniped
presence at the dam during the spring
[[Page 44880]]
months has been recorded since 2002 and during fall/winter months
starting in 2011 to assess the impact of predation on adult salmonids
and other fish (Tidwell et al. 2019).
Estimated take was calculated using the maximum daily number of
individuals observed at Bonneville dam (Tidwell et al. 2019),
multiplied by the total number of work days (61). The maximum daily
number of animals observed at the dam between August 15 and December 31
was used for both California sea lions (3 in 2015 and 2017) and Steller
sea lions (56 in 2016). No harbor seals were observed during the fall/
winter sampling period. However, only one of the three tailraces was
monitored during the fall/winter months and only when sea lion
abundance was >=20 animals. Therefore, NMFS multiplied the number of
observed California and Steller sea lions by three to account for
potential animals at all of the tailraces. Since there were no harbor
seals observed during the fall/winter period, NMFS used the maximum
daily observation from the spring observation period (3 in 2006) during
which all three tailraces were monitored. These estimates assume that
if an animal transits the reach of river where driving takes place it
will pass through the Level B isopleth since in most cases the radius
would be larger than the width of the river in most cases. Table 7
depicts the stocks NMFS proposes to authorize for take, the numbers
proposed for authorization, and the percentage of the stock taken.
Table 7--Level B Harassment Take Estimates for the King Pile Marker Project
----------------------------------------------------------------------------------------------------------------
Percentage of
Species Level B take Stock abundance stock taken
----------------------------------------------------------------------------------------------------------------
California Sea Lion.......................................... 549 296,750 0.2
Stellar Sea Lion............................................. 10,248 41,638 24.6
Harbor Seal.................................................. 183 * 24,732 0.7
----------------------------------------------------------------------------------------------------------------
* There is no current estimate of abundance available for this stock since most recent abundance estimate is >8
years old. Abundance value provided represents best available information from 1999.
Proposed Mitigation
In order to issue an IHA under Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) the practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In addition to the measures described later in this section, the
Corps must employ the following standard mitigation measures:
Conduct briefings between construction supervisors and
crews and the marine mammal monitoring team prior to the start of all
pile driving activity, and when new personnel join the work, to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures;
For in-water heavy machinery work other than pile driving
(e.g., standard barges, tug boats), if a marine mammal comes within 10
m, operations shall cease and vessels shall reduce speed to the minimum
level required to maintain steerage and safe working conditions. This
type of work could include the following activities: (1) Movement of
the barge to the pile location; or (2) positioning of the pile on the
substrate via a crane (i.e., stabbing the pile);
Work may only occur during daylight hours, when visual
monitoring of marine mammals can be conducted;
For any marine mammal species for which take by Level B
harassment has not been requested or authorized, in-water pile
installation will shut down immediately when the animals are sighted;
If take by Level B harassment reaches the authorized limit
for an authorized species, pile installation will be stopped as these
species approach the Level B harassment zone to avoid additional take
of them.
Establishment of Shutdown Zones--For all pile driving activities,
the Corps establish a shutdown zone. The purpose of a shutdown zone is
generally to define an area within which shutdown of activity would
occur upon sighting of a marine mammal (or in anticipation of an animal
entering the defined area). Shutdown zones will vary based on the type
of driving activity and by marine mammal hearing group. Shutdown zones
during impact and vibratory driving will be 10 m for all species, with
the exception of a 60-m shutdown zone for harbor seals during impact
driving activities. In all cases, the proposed shutdown zones are
larger than the calculated Level A harassment isopleths shown in Table
6. The placement of protected species observers (PSOs) during all pile
driving activities (described in detail in the Proposed Monitoring and
Reporting Section) will ensure that the entirety of all shutdown zones
are visible during pile installation.
Establishment of Monitoring Zones for Level B Harassment--The Corps
will establish monitoring zones, based on the Level B harassment
isopleths which are
[[Page 44881]]
areas where SPLs are equal to or exceed the 160 dB rms threshold for
impact driving and the 120 dB rms threshold during vibratory driving.
Monitoring zones provide utility for observing by establishing
monitoring protocols for areas adjacent to the shutdown zones.
Monitoring zones enable observers to be aware of and communicate the
presence of marine mammals in the project area outside the shutdown
zone and thus prepare for a potential cease of activity should the
animal enter the shutdown zone. In the unlikely event that a cetacean
enters the Level B harassment zones work will stop immediately until
the animal either departs the zone or is undetected for 15 minutes.
Distances to the Level B harassment zones are depicted in Table 6. In
addition, the Corps will establish minimum allowable work distances
between adjacent work platforms, based on monitoring zone isopleths, to
ensure that there is no overlap of behavioral harassment zones.
Sound Attenuation--Bubble curtains will be used during any impact
pile driving of piles located in water greater than 2 ft. in depth. The
bubble curtain will be operated in a manner consistent with the
following performance standards:
a. The bubble curtain will distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column;
b. The lowest bubble ring will be in contact with the mudline for
the full circumference of the ring, and the weights attached to the
bottom ring shall ensure 100 percent mudline contact. No parts of the
ring or other objects shall prevent full mudline contact; and
c. Air flow to the bubblers must be balanced around the
circumference of the pile.
Soft Start--The use of a soft-start procedure are believed to
provide additional protection to marine mammals by providing warning
and/or giving marine mammals a chance to leave the area prior to the
hammer operating at full capacity. For impact pile driving, contractors
will be required to provide an initial set of strikes from the hammer
at reduced percent energy, each strike followed by no less than a 30-
second waiting period. This procedure will be conducted a total of
three times before impact pile driving begins. Soft start is not
required during vibratory pile driving activities. A soft start must be
implemented at the start of each day's impact pile driving and at any
time following cessation of impact pile driving for a period of thirty
minutes or longer. If a marine mammal is present within the shutdown
zone, soft start will be delayed until the animal is observed leaving
the shutdown zone. Soft start will begin only after the PSO has
determined, through sighting, that the animal has moved outside the
shutdown zone or 15 minutes have passed without being seen in the zone.
If a marine mammal is present in the Level B harassment zone, soft
start may begin and a Level B take will be recorded for authorized
species. Soft start up may occur whether animals enter the Level B zone
from the shutdown zone or from outside the monitoring area.
Pre-Activity Monitoring--Prior to the start of daily in-water
construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs will observe the shutdown and monitoring
zones for a period of 30 minutes. The shutdown zone will be cleared
when a marine mammal has not been observed within the zone for that 30-
minute period. If a marine mammal is observed within the shutdown zone,
a soft-start cannot proceed until the animal has left the zone or has
not been observed for 15 minutes. If the Level B harassment zone has
been observed for 30 minutes and marine mammals are not present within
the zone, soft start procedures can commence and work can continue even
if visibility becomes impaired within the Level B harassment zone. When
a marine mammal permitted for take by Level B harassment is present in
the Level B harassment zone, pile driving activities may begin and take
by Level B will be recorded. As stated above, if the entire Level B
harassment zone is not visible at the start of construction, pile
driving activities can begin. If work ceases for more than 30 minutes,
the pre-activity monitoring of both the Level B harassment and shutdown
zone will commence.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Visual Monitoring
Monitoring would be conducted 30 minutes before, during, and 30
minutes 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. Pile driving activities
include the time to install 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.
There will be at least one PSO employed at all king pile
installation locations during all pile driving activities. PSO will not
perform duties
[[Page 44882]]
for more than 12 hours in a 24-hour period. The PSO would be positioned
close to pile driving activities at the best practical vantage point.
As part of monitoring, PSOs would scan the waters using binoculars,
and/or spotting scopes, and would use a handheld GPS or range-finder
device to verify the distance to each sighting from the project site.
All PSOs would be trained in marine mammal identification and behaviors
and are required to have no other project-related tasks while
conducting monitoring. In addition, PSOs will monitor for marine
mammals and implement shutdown/delay procedures when applicable by
calling for the shutdown to the hammer operator. Qualified observers
are trained and/or experienced professionals, 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;
Independent observers (i.e., not construction personnel);
Observers must have their CVs/resumes submitted to and
approved by NMFS;
Advanced education in biological science or related field
(i.e., undergraduate degree or higher). Observers may substitute
education or training for experience;
Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
At least one observer must have prior experience working
as an observer;
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.
Reporting
A draft marine mammal monitoring report must be submitted to NMFS
within 90 days after the completion of pile driving activities. This
reports will include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated PSO data
sheets. Specifically, the reports must include:
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;
An estimate of total take based on proportion of the
monitoring zone that was observed; and
Other human activity in the area.
If no comments are received from NMFS within 30 days, that phase's
draft final report will constitute the final report. If comments are
received, a final report for the given phase addressing NMFS comments
must be submitted within 30 days after receipt of comments. In the
unanticipated event that the specified activity clearly causes the take
of a marine mammal in a manner prohibited by the IHAs (if issued), such
as an injury, serious injury or mortality, the Corps would immediately
cease the specified activities and report the incident to the Chief of
the Permits and Conservation Division, Office of Protected Resources,
NMFS, and the West Coast Regional Stranding Coordinator. The report
would include the following information:
Description of the incident;
Environmental conditions (e.g., Beaufort sea state,
visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Species identification or description of the animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS would work with the Corps to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. The Corps would not be able
to resume their activities until notified by NMFS via letter, email, or
telephone.
In the event that the Corps discovers an injured or dead marine
mammal, and the lead PSO 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 as described in the next paragraph),
the Corps would immediately report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources, NMFS,
and the West Coast Regional Stranding Coordinator. The report would
include the same information identified in the paragraph above.
Activities would be able to continue while NMFS reviews the
circumstances of the incident. NMFS would work with the Corps to
determine whether modifications in the activities are appropriate.
In the event that the Corps discovers an injured or dead marine
mammal and the lead PSO determines that the injury or death is not
associated with or related to the activities authorized in these IHAs
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), the Corps would report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources, NMFS, and the West Coast Regional Stranding
Coordinator, within 24 hours of the discovery. The Corps would provide
photographs, video footage (if available), or other documentation of
the stranded animal sighting to NMFS and the Marine Mammal Stranding
Network.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
[[Page 44883]]
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
To avoid repetition, our analysis applies to all species listed in
Table 7, given that NMFS expects the anticipated effects of the
proposed pile driving to be similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, NMFS has identified species-specific factors to
inform the analysis.
NMFS does not anticipate that serious injury or mortality would
occur as a result of the Corps' proposed activity. As stated in the
proposed mitigation section, shutdown zones will be established and
monitored that equal or exceed calculated Level A harassment isopleths
during all pile driving activities.
Behavioral responses of marine mammals to pile driving during the
King Pile Marker Project are expected to be mild, short term, and
temporary. Marine mammals within the Level B harassment zones may not
show any visual cues they are disturbed by activities or they could
become alert, avoid the area, leave the area, or display other mild
responses that are not observable such as changes in vocalization
patterns. Given the short duration of noise-generating activities (less
than 90 minutes of combined daily impact and vibratory driving at 68
separate locations over 61 days, any harassment would be likely be
intermittent and temporary.
In addition, for all species there are no known biologically
important areas (BIAs) within the lower Columbia River and no ESA-
designated marine mammal critical habitat. The lower Columbia River
represents a very small portion of the total habitat available to the
pinniped species for which NMFS is proposing to authorize take. More
generally, there are no known calving or rookery grounds within the
project area, the project area represents a small portion of available
foraging habitat, and the duration of noise-producing activities
relatively is short, meaning impacts on marine mammal feeding for all
species should be minimal.
Any impacts on marine mammal prey that would occur during the
Corps' proposed activity would have at most short-terms effects on
foraging of individual marine mammals while transiting between the
South Jetty at the Mouth of the Columbia River and Bonneville Dam
located 146 miles upstream. Better feeding opportunities exist at these
two locations which is why pinnipeds tend to congregate in these areas.
Therefore, indirect effects on marine mammal prey during the
construction are not expected to be substantial, and these
insubstantial effects would therefore be unlikely to cause substantial
effects on individual marine mammals or the populations of marine
mammals as a whole.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
The Corps would implement mitigation measures including
bubble curtains and soft-starts during impact pile driving as well as
shutdown zones that exceed Level A harassment zones for authorized
species, such that Level A harassment is neither anticipated nor
authorized;
Anticipated incidents of Level B harassment consist of, at
worst, temporary modifications in behavior;
There are no BIAs or other known areas of particular
biological importance to any of the affected stocks impacted by the
activity within the Columbia River estuary or lower Columbia River;
The project area represents a very small portion of the
available foraging area for all marine mammal species and anticipated
habitat impacts are minimal; and
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
Table 7 in the Marine Mammal Occurrence and Take Calculation and
Estimation section presents the number of animals that could be exposed
to received noise levels that may result in take by Level B harassment
from the Corps' proposed activities. Our analysis shows that less than
25 percent of the Steller sea lion stock could be taken. Less than one
percent of California sea lion and harbor seal stocks are expected to
be taken. Given that numbers for Steller sea lions were derived from
limited observation at Bonneville Dam, it is likely that many of these
takes will be repeated takes of the same animals over multiple days. As
such, the take estimate serves as a good estimate of instances of take,
but is likely an overestimate of individuals taken, so actual
percentage of stocks taken would be even lower. We also emphasize the
fact that the lower Columbia River represents a very small portion of
the stock's large range, which extends from southeast Alaska to
southern California. It is unlikely that one quarter of the entire
stock would travel in excess of 137 miles upstream to forage at
Bonneville Dam on the Columbia River.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action.
[[Page 44884]]
Endangered Species Act (ESA)
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the Corps for conducting pile driving activities on the
Columbia River between September 15 and November 30, 2019, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHA for the proposed
[action]. We also request at this time comment on the potential renewal
of this proposed IHA as described in the paragraph below. Please
include with your comments any supporting data or literature citations
to help inform decisions on the request for this IHA or a subsequent
Renewal.
On a case-by-case basis, NMFS may issue a one-year IHA renewal with
an additional 15 days for public comments when (1) another year of
identical or nearly identical activities as described in the Specified
Activities section of this notice is planned or (2) the activities as
described in the Specified Activities section of this notice would not
be completed by the time the IHA expires and a Renewal would allow for
completion of the activities beyond that described in the Dates and
Duration section of this notice, provided all of the following
conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal are identical to the activities analyzed under the
initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take
because only a subset of the initially analyzed activities remain to be
completed under the Renewal).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for Renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: August 20, 2019.
Cathryn E. Tortorici,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2019-18351 Filed 8-26-19; 8:45 am]
BILLING CODE 3510-22-P