[Federal Register Volume 84, Number 67 (Monday, April 8, 2019)]
[Notices]
[Pages 13892-13906]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-06885]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XG627
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Aldo's Seawall Replacement Project
in Santa Cruz, California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the Santa Cruz Port District
(Port District) for authorization to take marine mammals incidental to
the Aldo's Seawall Replacement Project in Santa Cruz, California (CA).
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an incidental harassment
authorization (IHA) to take marine mammals incidental to 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 May 8,
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 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities 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: Amy Fowler, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. 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.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in 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 August 27, 2018, NMFS received a request from the Port District
for an IHA to take marine mammals incidental to the Aldo's Seawall
Replacement Project in the Santa Cruz Small Craft Harbor (harbor). The
application was deemed adequate and complete on March 21, 2019. The
Port District's request is for take of four species of marine mammals
by Level B harassment and Level A harassment. Neither the Port District
nor NMFS expects serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
The Port District is planning to replace the existing seawall
located below Aldo's Restaurant along the southwest bank of the Santa
Cruz Small Craft Harbor beginning in June 2019. The original seawall
was constructed between 1963 and 1964 and has deteriorated to the point
that Aldo's Harbor Restaurant voluntarily closed in
[[Page 13893]]
2016. The proposed project involves demolishing the existing restaurant
structure and timber pile supported restaurant deck, modifying a dock
gangway landing, removing timber piles supporting the public wharf,
removing and reinstalling rip-rap to accept the new sheet pile wall,
predrilling for new sheet piles, and installing a new steel sheet pile
seawall with concrete pile cap and tie-backs in front of the existing
seawall. Removing old timber piles and installing new steel sheet piles
has the potential to harass marine mammals within the harbor and
outside of the harbor in Monterey Bay.
Dates and Duration
Construction would occur between June 15 and November 1, 2019.
Construction timing is restricted by salmonid migration to avoid and
minimize potential impacts to steelhead trout (Oncorhynchus mykiss)
that may occur in the harbor. Construction would occur only during
daylight hours and during low tide, as feasible. The entire project is
expected to take 18 weeks, with approximately 28 days of in-water work.
Four timber piles would be removed over two days. Ninety sheet piles
would be driven over 15 days at a rate of six piles per day. The
remaining nine days of in-water work would involve pre-drilling to
prepare the substrate for driving of sheet piles, and removing and
reinstalling rip-rap around the seawall.
Specific Geographic Region
The harbor is located in Santa Cruz, California, off of Monterey
Bay (see Figure 1 of the IHA application). The lower portion of the
harbor runs primarily north-south while the upper portion (north of the
Murray Street bridge) extends to the northeast (see Figures 2a and 2b
in the IHA application). The harbor is less than 300 feet (ft) (91.4
meters (m)) wide at the mouth. The entrance to the harbor is marked by
Walton Lighthouse, which sits atop a rock jetty extending into Monterey
Bay. Aldo's Restaurant is located on the west side of the harbor. The
harbor is entirely developed, consisting of docks, boat launches, a
boat yard, and other facilities that provide harbor support services.
Detailed Description of Specific Activity
The existing Aldo's restaurant, concrete foundation, and timber
pile supported deck will be removed. The existing timber piles
supporting the deck will remain. All structure removal will occur above
the water and sound levels associated with the demolition are not
likely to be significantly different from noise associated with regular
harbor activities, such as large boat and vehicle traffic. Existing
structure removal is not expected to result in take of marine mammals,
and therefore will not be discussed further in this document.
On the south side of the restaurant, a portion of the existing rip-
rap will be temporarily removed and stockpiled to prevent interference
with installing the new seawall, and the remaining rip-rap will be
protected in place. Approximately 300-400 square ft (91-122 square m)
of rip-rap will be removed. This activity would occur at low tide and
no equipment would enter the water. Following installation of the new
seawall, the rip-rap that was previously removed and stockpiled would
be reinstalled. Removal and subsequent replacement of rip-rap is not
expected to result in take of marine mammals, and therefore will not be
discussed further in this document.
On the north side of the restaurant, the gangway to AA-dock and a
portion of the public wharf (see Figure 2a in the IHA application)
would be temporarily removed to allow sheet pile installation.
Following installation of the new seawall, the existing aluminum
gangway to AA-dock would be reinstalled. The portion of the existing
public wharf that was removed would be reframed and replaced in-kind.
Modification of the gangway and public wharf are not expected to result
in take, and therefore will not be discussed further in this document.
Four 16 inch (in) (40.6 centimeter (cm)) timber piles supporting
the public wharf would be permanently removed. These piles would be
removed using a vibratory driver to reduce the extraction effort and
the likelihood that the pile would break. The piles would be removed
using land-based equipment. No new timber piles would be installed.
The existing steel sheet pile wall, tie-rods, and concrete anchors
would be abandoned in place. The new steel sheet pile wall would be
installed on the water side of the existing seawall, with rock placed
in the void between the existing and new walls. The new seawall would
extend approximately two feet further into harbor waters than the
existing seawall. The new seawall will be composed of 90 0.5 m (1.6 ft)
steel sheet piles, which will be driven in pairs.
Prior to installing the sheet piles, the contractor would pre-drill
the substrate, drilling three 15 cm (6 in) diameter holes to the tip
elevation for each pair of sheet piles. Pre-drilling would use land-
based equipment, with only the auger in the water. Pre-drilling is
expected to occur over five days but the actual duration of drilling
activities is expected to be much shorter. NMFS has authorized take in
association with certain types of drilling in other project (e.g., 84
FR 4777; February 19, 2019), but those typically have much larger holes
being drilled and/or othr circumstances leading to an expectation of
louder sound levels than are expected here. Because of the small
drilled hole size and short duration of drilling, acoustic impacts from
pre-drilling are not expected to rise to the level of a take, take is
not proposed to be authorized here and the effects of pre-drilling will
not be discussed further in this document.
The 90 sheet piles will be driven over approximately 15 days, at a
rate of six piles per day. The contractor would first use a vibratory
hammer to sink the sheet piles through the soil over the bedrock
(sandstone). Once the sheet piles have been sunk into the substrate,
the contractor would use an impact hammer to drive the sheet piles into
the substrate to a maximum depth of embedment of 2-2.5 m (7-8 ft).
Based on the varying density of the bedrock and the required depth of
embedment, each sheet pile would require a maximum of 300 strikes (600
strikes per pair) from the impact hammer.
Table 1--Summary of Pile Driving Activities
----------------------------------------------------------------------------------------------------------------
Maximum daily
Pile type Method Number of Piles per day Strikes per duration
piles pile (hours)
----------------------------------------------------------------------------------------------------------------
16 in timber.................. Vibratory 4 2 N/A 6
removal.
0.5 m steel sheet............. Vibratory 90 6 N/A 6
installation.
0.5 m steel sheet............. Impact 90 6 300 N/A
installation.
----------------------------------------------------------------------------------------------------------------
[[Page 13894]]
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 IHA application summarize available
information regarding status and trends, distribution and habitat
preferences, and behavior and life history, of the potentially affected
species. Additional information regarding population trends and threats
may be found in NMFS's Stock Assessment Reports (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 2 lists all species with expected potential for occurrence in
the harbor and surrounding waters of Monterey Bay 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 (2018). PBR
is defined by the MMPA as the maximum number of animals, not including
natural mortalities, that may be removed from a marine mammal stock
while allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's U.S. Pacific SARs. All values presented in Table 2 are the most
recent available at the time of publication and are available in the
2017 SARs (Caretta et al., 2018) and draft 2018 SARs (available online
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).
Table 2--Marine Mammals With Potential Presence Within the Proposed Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Common bottlenose dolphin....... Tursiops truncatus..... California Coastal..... -/-; N 453 (0.06, 346, 2011). 2.7 >2.0
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Monterey Bay........... -/-; N 3,715 (0.51, 2,480, 25 0
2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S.................... -/-; N 257,606 (N/A, 233,515, 14,011 >319
2014).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... California............. -/-; N 30,968 (N/A, 27,348, 1,641 43
2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
All species that could potentially occur in the proposed project
areas are included in Table 2. As described below, all four species
(with four managed stocks) temporally and spatially co-occur with the
activity to the degree that take is reasonably likely to occur, and we
have proposed authorizing it. In addition, the southern sea otter
(Enhydra lutris nereis) may be found in the harbor. However, southern
sea otters are managed by the U.S. Fish and Wildlife Service and are
not considered further in this document.
Harbor Seal
Harbor seals are residential year-round within the harbor,
primarily utilizing harbor docks as nighttime haulout locations. The
greatest numbers of hauled-out seals have been observed in the harbor
at B, F, and FF docks, as well as the floating docks near the small
boat launch (between docks F and FF) and the boat yard docks (T) (see
Figures 2a and 2b in the IHA application). Most seals leave the harbor
shortly after dawn, but some remain and forage within the harbor. The
greatest concentrations of foraging seals are typically just south of
the Murray Street Bridge by the Live Bait dock (Dock S) (see Figure 2a
in the IHA application). During the molting season, seals have been
observed remaining at their nighttime haulouts several hours after
dawn. Molting season in Santa Cruz is estimated to occur between late
April and July (Seal Conservancy 2017; Vanderhoof and Allen 2005).
During 2018 surveys, molting was observed from June through July 10.
The harbor is not a known rookery for harbor seals; the closest known
rookeries are Elkhorn Slough, Lover's Point State Marine
[[Page 13895]]
Reserve, and Point Lobos (25-50 kilometers (km) (15.5-31 miles (mi))
south and southeast of the harbor).
California Sea Lion
Adult male California sea lions are resident in Monterey Bay
outside of breeding season, and juvenile males are present in Monterey
Bay year-round. California sea lions are visitors to the harbor,
occasionally using the harbor for foraging and the docks and other
harbor features for haulouts. Larger numbers of California sea lions
may be present in the harbor waters when fish runs occur within the
harbor. Weather, currents, seasonal upwelling conditions, and other
oceanographic factors periodically bring anchovies, sardines, and other
prey species into the harbor, drawing larger numbers of birds and
pinnipeds. California sea lions are primarily observed using the docks
of the lower harbor (south of the Murray Street bridge, see Figure 2a
in the IHA application). The closest rookeries are Ano Nuevo Island (35
km (21.7 mi) northwest) and the Farallon Islands (120 km (74.6 mi)
northwest) (Marine Mammal Center 2018; Wheeler 2001; Keith et al.,
1984).
Bottlenose Dolphin
A resident population of over 50 coastal bottlenose dolphins occurs
in Monterey Bay (Hwang et al., 2014). Sixty-eight uniquely marked
individuals were observed during surveys in the early 1990s (Feinholz
1996). This population preferentially uses the northern part of
Monterey Bay but some of the photo-identified dolphins have been
observed as far south as the Southern California Bight (Hwang et al.,
2014). Bottlenose dolphins are not known to occur within the harbor
itself, but may be present in the nearshore waters immediately outside
the mouth of the harbor.
Harbor Porpoise
Resident harbor porpoises are known to occur in the coastal waters
of Monterey Bay. The bathymetry of the northern Monterey Bay results in
a relatively high density of harbor porpoises in the nearshore areas
(Jacobsen et al., 2017; Jacobsen et al., 2015). Porpoises in the
northern part of Monterey Bay represent approximately 15 percent of the
stock (Forney et al., 2014). Harbor porpoises are the most common
nearshore cetacean in Monterey Bay and although they have not been
observed within the harbor, they have been observed outside the harbor
(Forney pers. comm. 2018).
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 dB
threshold from the normalized composite audiograms, with the exception
for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall
et al. (2007) retained. The functional groups and the associated
frequencies are indicated below (note that these frequency ranges
correspond to the range for the composite group, with the entire range
not necessarily reflecting the capabilities of every species within
that group):
Low-frequency cetaceans (mysticetes): Generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): Generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz.
Pinnipeds in water; Phocidae (true seals): Generalized
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
Pinnipeds in water; Otariidae (eared seals): Generalized
hearing is estimated to occur between 60 Hz and 39 kHz.
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Four marine mammal species (two cetacean and two pinniped (one otariid
and one phocid) species) have the reasonable potential to co-occur with
the proposed survey activities. Please refer to Table 2. Of the
cetacean species that may be present, one is classified as a mid-
frequency cetacean (i.e., all delphinid and ziphiid species and the
sperm whale), and one is classified as a high-frequency cetacean (i.e.,
harbor porpoise and Kogia spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far. The sound level of an area is defined by the
total acoustical energy being generated by known and unknown sources.
These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
[[Page 13896]]
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al. 1995). The result is that, depending
on the source type and its intensity, sound from the specified activity
may be a negligible addition to the local environment or could form a
distinctive signal that may affect marine mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving, and vibratory pile
removal. The sounds produced by these activities fall into one of two
general sound types: Impulsive and non-impulsive. Impulsive sounds
(e.g., explosions, gunshots, sonic booms, impact pile driving) are
typically transient, brief (less than 1 second), broadband, and consist
of high peak sound pressure with rapid rise time and rapid decay (ANSI
1986; NIOSH 1998; ANSI 2005; NMFS 2018). Non-impulsive sounds (e.g.
aircraft, machinery operations such as drilling or dredging, vibratory
pile driving, and active sonar systems) can be broadband, narrowband or
tonal, brief or prolonged (continuous or intermittent), and typically
do not have the high peak sound pressure with raid rise/decay time that
impulsive sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward 1997 in Southall et al. 2007).
Two types of pile hammers would be used on this project: impact and
vibratory. Impact hammers operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak SPLs may be
180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al. 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards 2002; Carlson et al. 2005).
The likely or possible impacts of the Port District's proposed
activity on marine mammals could involve both non-acoustic and acoustic
stressors. Potential non-acoustic stressors could result from the
physical presence of the equipment and personnel; however, any impacts
to marine mammals are expected to primarily be acoustic in nature.
Acoustic stressors include effects of heavy equipment operation during
pile installation and removal and drilling.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal is the primary means by which
marine mammals may be harassed from the Port District's specified
activity. In general, animals exposed to natural or anthropogenic sound
may experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al. 2007). In general, exposure to
pile driving and drilling noise has the potential to result in auditory
threshold shifts and behavioral reactions (e.g., avoidance, temporary
cessation of foraging and vocalizing, changes in dive behavior).
Exposure to anthropogenic noise can also lead to non-observable
physiological responses such an increase in stress hormones. Additional
noise in a marine mammal's habitat can mask acoustic cues used by
marine mammals to carry out daily functions such as communication and
predator and prey detection. The effects of pile driving and drilling
noise on marine mammals are dependent on several factors, including,
but not limited to, sound type (e.g., impulsive vs. non-impulsive), the
species, age and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the pile and the animal,
received levels, behavior at time of exposure, and previous history
with exposure (Wartzok et al. 2004; Southall et al. 2007). Here we
discuss physical auditory effects (threshold shifts) followed by
behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al. 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960;
Kryter et al. 1966; Miller 1974; Ahroon et al. 1996; Henderson et al.
2008). PTS levels for marine mammals are estimates, as with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al. 2008), there are no empirical data measuring PTS in
marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS 2018).
Temporary Threshold Shift (TTS)--A temporary, reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS 2018). Based on data from cetacean TTS measurements (see
Southall et al. 2007), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et
al. 2000; Finneran et al. 2000, 2002). As described in Finneran (2015),
marine
[[Page 13897]]
mammal studies have shown the amount of TTS increases with cumulative
sound exposure level (SELcum) in an accelerating fashion: At
low exposures with lower SELcum, the amount of TTS is
typically small and the growth curves have shallow slopes. At exposures
with higher higher SELcum, the growth curves become steeper
and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al. 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al. 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran 2015). Additionally, the existing marine mammal TTS data come
from a limited number of individuals within these species. No data are
available on noise-induced hearing loss for mysticetes. For summaries
of data on TTS in marine mammals or for further discussion of TTS onset
thresholds, please see Southall et al. (2007), Finneran and Jenkins
(2012), Finneran (2015), and Table 5 in NMFS (2018). Installing piles
requires a combination of impact pile driving and vibratory pile
driving. For the project, these activities would not occur at the same
time and there would likely be pauses in activities producing the sound
during each day. Given these pauses and that many marine mammals are
likely moving through the action area and not remaining for extended
periods of time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal and drilling also has the potential to behaviorally disturb
marine mammals. Available studies show wide variation in response to
underwater sound; therefore, it is difficult to predict specifically
how any given sound in a particular instance might affect marine
mammals perceiving the signal. If a marine mammal does react briefly to
an underwater sound by changing its behavior or moving a small
distance, the impacts of the change are unlikely to be significant to
the individual, let alone the stock or population. However, if a sound
source displaces marine mammals from an important feeding or breeding
area for a prolonged period, impacts on individuals and populations
could be significant (e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC
2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff 2006). Behavioral responses to sound are
highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al. 1995; Wartzok et al. 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). In
general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans. Please see Appendices B-C of Southall et al.
(2007) for a review of studies involving marine mammal behavioral
responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.
2001; Nowacek et al. 2004; Madsen et al. 2006; Yazvenko et al. 2007). A
determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
In 2016, the Alaska Department of Transportation and Public
Facilities (ADOT&PF) documented observations of marine mammals during
construction activities (i.e., pile driving and down-hole drilling) at
the Kodiak Ferry Dock (see 80 FR 60636 for Final IHA Federal Register
notice). In the marine mammal monitoring report for that project (ABR
2016), 1,281 Steller sea lions were observed within the behavioral
disturbance zone during pile driving or drilling (i.e., documented as
Level B harassment take). Of these, 19 individuals demonstrated an
alert behavior, 7 were fleeing, and 19 swam away from the project site.
All other animals (98 percent) were engaged in activities such as
milling, foraging, or fighting and did not change their behavior. In
addition, two sea lions approached within 20 meters of active vibratory
pile driving activities. Three harbor seals were observed within the
disturbance zone during pile driving activities; none of them displayed
disturbance behaviors. Fifteen killer whales and three harbor porpoise
were also observed within the Level B harassment zone during pile
driving. The killer whales were travelling or milling while all harbor
porpoises were travelling. No signs of disturbance were noted for
either of these species. Given
[[Page 13898]]
the similarities in activities and habitat and the fact the same
species are involved, we expect similar behavioral responses of marine
mammals to the specified activity. That is, disturbance, if any, is
likely to be temporary and localized (e.g., small area movements).
Monitoring reports from other recent pile driving projects have
observed similar behaviors.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation) (Richardson et al. 1995). Masking occurs when
the receipt of a sound is interfered with by another coincident sound
at similar frequencies and at similar or higher intensity, and may
occur whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g. on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
harbor houses hundreds of small craft vessels that transit through the
harbor waters on a regular basis; therefore, background sound levels in
the harbor are already elevated.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels exceeding the acoustic thresholds. 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.
Marine Mammal Habitat Effects
The Port District's construction activities within the harbor could
have localized, temporary impacts on marine mammal habitat by
increasing in-water sound pressure levels and slightly decreasing water
quality. Construction activities are of short duration and would likely
have temporary impacts on marine mammal habitat through increases in
underwater sound. Increased noise levels may affect acoustic habitat
(see masking discussion above) and adversely affect marine mammal prey
in the vicinity of the project area (see discussion below). During
impact pile driving, elevated levels of underwater noise would ensonify
the harbor where both fish and mammals may occur and could affect
foraging success.
In-water pile driving and pile removal would also cause short-term
effects on water quality due to increased turbidity. Local currents are
anticipated to disburse suspended sediments produced by project
activities at moderate to rapid rates depending on tidal stage. The
Port District would employ standard construction best management
practices, thereby reducing any impacts. Therefore, the impact from
increased turbidity levels is expected to be discountable.
In-Water Construction Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in Monterey Bay and does not include
any BIAs or ESA-designated critical habitat. Foraging efforts within
the harbor are minimal, and the narrow mouth of the harbor would
restrict sound transmission into Monterey Bay to a narrow band of sound
in the southeastern direction. Pile installation/removal and drilling
may temporarily increase turbidity resulting from suspended sediments.
Any increases would be temporary, localized, and minimal. The Port
District must comply with state water quality standards during these
operations by limiting the extent of turbidity to the immediate project
area. In general, turbidity associated with pile installation is
localized to about a 25-foot radius around the pile (Everitt et al.
1980). Cetaceans are not expected to enter the harbor and be close
enough to the project pile driving areas to experience effects of
turbidity, and any pinnipeds would likely be transiting the area and
could avoid localized areas of turbidity. Therefore, the impact from
increased turbidity levels is expected to be discountable to marine
mammals. Furthermore, pile driving and removal at the project site
would not obstruct movements or migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity in Monterey Bay.
The duration of the construction activities is relatively short,
with pile driving and removal activities expected to take only 17 days.
Each day, construction would occur for only a few hours during the day.
Impacts to habitat and prey are expected to be temporary and minimal
based on the short duration of activities.
In-Water Construction Effects on Potential Prey (Fish)
Construction activities would produce continuous (i.e., vibratory
pile driving) and pulsed (i.e. impact driving) sounds. Fish react to
sounds that are especially strong and/or intermittent low-frequency
sounds. Short duration, sharp
[[Page 13899]]
sounds can cause overt or subtle changes in fish behavior and local
distribution. Hastings and Popper (2005) identified several studies
that suggest fish may relocate to avoid certain areas of sound energy.
Additional studies have documented effects of pile driving on fish,
although several are based on studies in support of large, multiyear
bridge construction projects (e.g., Scholik and Yan 2001, 2002; Popper
and Hastings 2009). Sound pulses at received levels of 160 dB may cause
subtle changes in fish behavior. SPLs of 180 dB may cause noticeable
changes in behavior (Pearson et al. 1992; Skalski et al. 1992). SPLs of
sufficient strength have been known to cause injury to fish and fish
mortality.
The most likely impact to fish from pile driving and drilling
activities at the project area would be temporary behavioral avoidance
of the area. The duration of fish avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution and behavior is anticipated. In general, impacts to marine
mammal prey species are expected to be minor and temporary due to the
short timeframe for the project.
Construction activities, in the form of increased turbidity, have
the potential to adversely affect fish in the project area. Increased
turbidity is expected to occur in the immediate vicinity (on the order
of 10 feet or less) of construction activities. However, suspended
sediments and particulates are expected to dissipate quickly within a
single tidal cycle. Given the limited area affected and high tidal
dilution rates any effects on fish are expected to be minor or
negligible. In addition, best management practices would be in effect,
which would limit the extent of turbidity to the immediate project
area.
In summary, given the short daily duration of sound associated with
individual pile driving and drilling events and the relatively small
areas being affected, pile driving and drilling activities associated
with the proposed action are not likely to have a permanent, adverse
effect on any fish habitat, or populations of fish species. Thus, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant or long-term consequences for
individual marine mammals, or to contribute to adverse impacts on their
populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the vibratory and impact pile hammers has the potential to result in
disruption of behavioral patterns for individual marine mammals. There
is also some potential for auditory injury (Level A harassment) to
result, primarily for high frequency cetaceans and phocids, because
predicted auditory injury zones are larger than for mid-frequency
species and otariids. However, due to the shape of the harbor and the
small overall ensonified area (see Figure 3 in IHA application),
auditory injury in high frequency cetaceans is not expected nor
proposed to be authorized. Auditory injury may occur in phocids within
the inner harbor area. The proposed mitigation and monitoring measures
are expected to minimize the severity of such taking to the extent
practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which 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-driving, drilling) and above 160 dB re 1 [mu]Pa (rms)
for non-explosive intermittent (e.g., impact pile driving) sources.
The Port District's proposed activity includes the use of
continuous (vibratory pile driving and removal) and impulsive (impact
pile driving) sources, and therefore the 120 and 160 dB re 1 [mu]Pa
(rms) thresholds are applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The Port District's proposed activity
includes the use of impulsive (impact pile driving) and non-impulsive
(vibratory pile driving and removal) sources.
[[Page 13900]]
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 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]Pa2s. 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 weighted function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., impact pile driving, vibratory
pile driving and removal). The entire lower harbor (see Figure 2a in
the IHA application) and a small, narrow band extending southeast from
the mouth of the harbor into Monterey Bay (see Figure 3 in the IHA
application) may be ensonified by project activities. Vessel traffic
within the harbor and out in Monterey Bay may contribute to elevated
background noise levels which may mask sounds produced by the project.
The distances to the Level A and Level B harassment thresholds were
calculated based on source levels from similar pile driving activities
in California and Washington. The Port District utilized in-water
measurements generated by the Greenbusch Group (2018) from the Seattle
Pier 62 project (83 FR 39709) to establish proxy sound source levels
for vibratory removal of the 16-inch timber piles. The results
determined unweighted rms ranging from 140 dB to 169 dB. NMFS analyzed
source measurements at different distances for all 63 individual timber
piles that were removed at Pier 62 and normalized the values to 10 m.
The results showed that the median is 152 dB SPLrms. This value was
used as the source level for vibratory removal of 16-inch timber piles
(Table 4). For vibratory and impact installation of steel sheet piles,
the Port District utilized reference source levels of vibratory and
impact driving of 24-inch (0.6 m) steel sheet piles from CalTrans
Technical Guidance for Assessment and Mitigation of the Hydroacoustic
Effects of Pile Driving on Fish (Buehler et al., 2015). Vibratory
driving of 24-inch (0.6 m) AZ steel sheet piles was found to have a
range of source levels between 160 and 165 dB (rms) at 10 m, but the
typical source level was 160 dB rms (Table 4). The proposed project
involves slightly smaller 0.5 m steel sheet piles, but the CalTrans
source levels are the best available proxy.
Table 4--Source Levels for Pile Driving Activities
----------------------------------------------------------------------------------------------------------------
SPLRMS (dB)
Activity SPLPK (dB) SEL (dB) Source
----------------------------------------------------------------------------------------------------------------
Vibratory timber pile removal n/a 152 n/a Greenbusch Group 2018.
Vibratory sheet pile 175 160 160 Buehler et al., 2015.
installation.
Impact sheet pile 205 190 180 Buehler et al., 2015.
installation.
----------------------------------------------------------------------------------------------------------------
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 (R 1/R 2),
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R 1 = the distance of the modeled SPL from the driven
pile, and
R 2 = the distance from the driven pile of the initial
measurement
A practical spreading value of fifteen is often used under
conditions, such as at the harbor, where water increases with depth as
the receiver moves away from the shoreline, resulting in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions. Practical spreading loss is
assumed here.
[[Page 13901]]
Using the practical spreading loss model, the Port District
determined the distance where the noise will fall below the behavioral
effects threshold for both continuous (vibratory pile driving and
removal) and intermittent (impact pile driving) sources (120 and 160 dB
dB re 1 [mu]Pa (rms), respectively). These distances are shown in Table
6 below.
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 closest distance at which,
if a marine mammal remained at that distance the whole duration of the
activity, it would not incur PTS. Inputs used in the User Spreadsheet,
and the resulting isopleths are reported below.
Table 5--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving Vibratory pile removal
Parameter Impact pile driving (sheet pile) (timber pile)
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used................. (E.1) Impact pile (A.1) Vibratory pile (A.1) Vibratory pile
driving. driving. driving.
Source Level......................... 180 dB SEL............. 160 dB RMS............. 152 dB RMS.
Weighting Factor Adjustment (kHz).... 2...................... 2.5.................... 2.5.
Number of strikes per pile........... 300.................... N/A.................... N/A.
Number of piles per day.............. 6...................... N/A.................... N/A.
Activity Duration (hours) within 24- N/A.................... 6...................... 6.
hour period.
Propagation (xLogR).................. 15LogR................. 15LogR................. 15LogR.
Distance of source level measurement 10..................... 10..................... 10.
(meters).
----------------------------------------------------------------------------------------------------------------
Table 6--Calculated Distances to Level A Harassment and Level B Harassment Isopleths During Pile Installation
and Removal
----------------------------------------------------------------------------------------------------------------
Level A harassment zone (meters)
---------------------------------------------------------------- Level B
Source High- Harassment
Mid-frequency frequency Phocid Otariid Zone (meters)
cetacean cetacean pinniped pinniped
----------------------------------------------------------------------------------------------------------------
Impact pile driving............. 33 1,111 499 36 1,000
Vibratory pile driving (sheet 2 29 12 1 4,642
pile)..........................
Vibratory pile removal (timber < 1 8 3 < 1 1,359
pile)..........................
----------------------------------------------------------------------------------------------------------------
While the calculated distances to the Level A and Level B
harassment isopleths are up to 4,642 m, the project occurs within a
nearly completely enclosed harbor, with only a narrow mouth leading out
into the larger Monterey Bay. The harbor is approximately 152 m wide at
the project site, and the furthest extent sound could travel in a
straight line within the harbor is approximately 610 m (see Figures 2a
and 2b in the IHA application). Depending on the pile location, sound
may travel out the mouth of the harbor, but only in a small narrow band
extending to the southeast (see Figure 3 in the IHA application).
Therefore, while the calculated distances to thresholds are large, the
actual ensonified area is significantly constrained by land.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
Harbor seals and California sea lions are regular occupants of the
harbor. Monitors from EcoSystems West conducted surveys of harbor docks
in May and June 2018 to determine the number of pinnipeds expected to
occur during the project. As stated previously, harbor seals are known
to use the harbor docks and other structures for nighttime haulouts.
Most surveys occurred at dawn to count the number of pinnipeds that may
be present at the beginning of each day of construction. Additional
daytime monitoring occurred in July and August 2018 during harbor
maintenance activities. These daytime surveys included counts of
pinnipeds hauled out and in the water. The maximum number of hauled out
harbor seals was 23 while up to three seals were observed in the water
during the day. Up to four California sea lions were observed using the
harbor during the day. Harbor porpoises and bottlenose dolphins do not
typically occur within the harbor, but may transit through the narrow
band of ensonified area that extends to the southeast of the harbor
entrance (see Figure 3 in the IHA application).
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate.
Level B Harassment--Level B takes of harbor seals and California
sea lions were estimated by multiplying the highest number of animals
observed within the harbor (23 harbor seals and four California sea
lions) by the days of activity (17 days). Level B harassment
[[Page 13902]]
take of harbor porpoises and bottlenose dolphins was estimated using
mean group size and the likelihood that a group of animals may enter
the ensonified area during the project. Mean group size of harbor
porpoises traveling through northern Monterey Bay was assumed to be
1.75 animals (Forney et al., 2014) and we assume that a group of
porpoises may pass through the ensonified band every other day during
construction (eight days total). Mean group size of bottlenose dolphins
was assumed to be eight animals (Weller et al., 2016) and we assume
that a group of dolphins may pass through the ensonified band every
other day during construction (eight days).
Level A Harassment --Level A harassment takes of harbor seals were
estimated by multiplying the highest number of seals observed in the
water during the day (three seals) by the number of days of impact pile
driving (15 days). Level A harassment is only expected and proposed to
be authorized for harbor seals during impact pile driving, due to the
relatively small Level A harassment isopleths for other species and
other activities. Mitigation measures (described in detail below) are
expected to eliminate any potential for Level A harassment of
California sea lions within the harbor. While the Level A harassment
zone for harbor porpoises is greater than that of harbor seals, harbor
porpoises are not expected to occur within the narrow band of sound
that may exceed the harassment threshold for sufficient duration to
experience Level A harassment (see Figures 1 and 3 in the IHA
application). Take of harbor porpoises by Level A harassment has not
been requested and is not proposed to be authorized.
Table 7--Estimated Take by Level A and Level B Harassment, by Species and Stock, Resulting From Proposed Port District Project Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed
Level B Level A Days of Total level Total level Total take as
Species Stock takes per takes per activity B take A take proposed percentage
day day take of stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal......................... California............. 23 3 17\a\ 391 45 436 1.41
California sea lion................. U.S.................... 4 0 17 68 0 68 0.03
Bottlenose dolphin.................. California Coastal..... 8 0 8\b\ 64 0 64 14.1
Harbor porpoise..................... Monterey Bay........... 2 0 8\b\ 16 0 16 0.43
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Days of activity for Level A take calculations is only 15 days of impact pile driving.
\b\ Harbor porpoises and bottlenose dolphins are expected to occur within the ensonified area every other day during construction activities.
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.
Mitigation for Marine Mammals and Their Habitat
In addition to the measures described later in this section, the
Port District will 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., pre-drilling, etc.), if a marine mammal comes within 10 m,
operations shall cease and equipment use reduced to minimum level
required to maintain safe working conditions. This type of work could
include the following activities: (1) Pre-drilling; or (2) positioning
of the pile on the substrate via a land-based crane;
Work may only occur during daylight hours, when visual
monitoring of marine mammals can be conducted;
For those marine mammals for which Level B harassment take
has not been requested, in-water pile installation/removal and drilling
will shut down immediately if such species are observed within or on a
path towards the monitoring zone (i.e., Level B harassment zone); and
If take 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.
The following measures are also included in the mitigation
requirements:
Establishment of Shutdown Zone for Level A Harassment--For all pile
driving and removal activities, the Port District must establish a
shutdown zone. The purpose of a shutdown zone is generally to define an
area within which shutdown of an activity would occur upon sighting of
a marine mammal (or in anticipation of an animal entering the defined
area). During all pile driving activities, a minimum shutdown zone of
25 m would be enforced (Table 8). A 40 m shutdown zone would be used
for California sea lions during impact pile driving to prevent Level A
harassment exposure (Table 8). Harbor porpoises and bottlenose dolphins
are not
[[Page 13903]]
expected to occur within the harbor, so instead of a standard shutdown
distance, the Port District will be required to shutdown impact pile
driving activities if these species are observed entering the harbor
(Table 8). A Protected Species Observer (PSO) will be stationed within
the harbor such that they have a view of the immediate area around the
pile driving as well as the areas north (toward the back of the harbor)
and south (toward the harbor entrance) of the project site.
Establishment of Monitoring Zones for Level B Harassment--The
calculated distances to the Level B harassment thresholds may exceed
the distance within the harbor that sound may travel in a linear
direction. The harbor is approximately 152 m wide at the project site,
and the furthest extent sound could travel in a straight line within
the harbor is approximately 610 m (see Figures 2a and 2b in the IHA
application). Sound may transmit in a narrow band into Monterey Bay
through the mouth of the harbor but the overall ensonified area is
relatively small. As stated above, a PSO will be stationed within the
harbor. Rather than a set distance-based monitoring zone, the PSOs will
monitor the entire observable harbor area (Table 8).
Table 8--Shutdown and Monitoring Zones by Project Activity
------------------------------------------------------------------------
Activity Shutdown zone (m) Monitoring zone
------------------------------------------------------------------------
Vibratory removal of timber All species: 25..... Entire observable
piles. harbor area.
Impact installation of steel Harbor seal: 25.....
sheet piles. California sea lion:
40.
Harbor porpoise and
bottlenose dolphin:
At mouth of harbor.
Vibratory installation of All species: 25.....
steel sheet piles.
All other in-water 10..................
activities (e.g., pre-
drilling).
------------------------------------------------------------------------
Soft Start--The use of soft-start procedures 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
would be required to provide an initial set of strikes from the hammer
at reduced energy, with each strike followed by a 30-second waiting
period. This procedure would be conducted a total of three times before
impact pile driving begins. Soft start would 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. Soft start is not required during vibratory pile driving and
removal activities.
Pre-Activity Monitoring--Prior to the start of daily in-water
construction activity, or whenever a break in pile driving/removal or
drilling 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 non-permitted
species are not present within the zone, soft start procedures can
commence and work can continue even if visibility becomes impaired
within the Level B monitoring zone. When a marine mammal permitted for
Level B harassment take is present in the Level B harassment zone,
activities may begin and Level B harassment take will be recorded. As
stated above, if the entire Level B harassment zone is not visible at
the start of construction, piling or drilling 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, as
well as other measures considered by NMFS, NMFS has preliminarily
determined that the proposed mitigation measures provide the means
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth, ``requirements pertaining to
the monitoring and reporting of such taking.'' The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Marine Mammal Visual Monitoring
Monitoring shall be conducted by NMFS-approved observers. A trained
[[Page 13904]]
observer shall be placed from the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Observer training must be provided prior to project start, and shall
include instruction on species identification (sufficient to
distinguish the species in the project area), description and
categorization of observed behaviors and interpretation of behaviors
that may be construed as being reactions to the specified activity,
proper completion of data forms, and other basic components of
biological monitoring, including tracking of observed animals or groups
of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
Monitoring would be conducted 30 minutes before, during, and 30
minutes after pile driving/removal and drilling 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 or removed. Pile driving/removal and drilling activities include
the time to install or remove a single pile or series of piles, as long
as the time elapsed between uses of the pile driving equipment is no
more than 30 minutes.
One PSO would be stationed at a location within the harbor that
allows full monitoring of the area immediately around the piles being
driven, as well as a view toward the back of the harbor and toward the
harbor entrance. The PSO would scan the waters using binoculars, and/or
spotting scopes if necessary, 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, monitoring will be conducted by
qualified observers, who will be placed at the best vantage point(s)
practicable to monitor for marine mammals and implement shutdown/delay
procedures when applicable by calling for the shutdown to the hammer
operator. The Port District would adhere to the following observer
qualifications:
(i) Independent observers (i.e., not construction personnel) are
required;
(ii) At least one observer must have prior experience working as an
observer;
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience;
(iv) Where a team of three or more observers are required, one
observer shall be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer; and
(v) The Port District shall submit observer CVs for approval by
NMFS.
Additional standard observer qualifications include:
Ability to conduct field observations and collect data
according to assigned protocols. Experience or training in the field
identification of marine mammals, including the identification of
behaviors;
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.
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving and removal and
drilling activities. It will include an overall description of work
completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report 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; and
Other human activity in the area.
If no comments are received from NMFS within 30 days, the draft
final report will constitute the final report. If comments are
received, a final report addressing NMFS comments must be submitted
within 30 days after receipt of comments.
In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by the IHA
(if issued), such as an injury, serious injury or mortality, the Port
District would immediately cease the specified activities and report
the incident to the 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 Port
District to determine what is necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. The Port District
would not be able to resume their activities until notified by NMFS via
letter, email, or telephone.
In the event that the Port District 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 Port District would immediately report the incident to
the Office of Protected Resources, NMFS, and the NMFS West Coast
Stranding Hotline and/or by email to 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
Port District to determine whether modifications in the activities are
appropriate.
In the event that the Port District 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 the IHA
(e.g., previously wounded animal, carcass with moderate
[[Page 13905]]
to advanced decomposition, or scavenger damage), the Port District
would report the incident to the Office of Protected Resources, NMFS,
and the NMFS West Coast Stranding Hotline and/or by email to the West
Coast Regional Stranding Coordinator, within 24 hours of the discovery.
The Port District 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
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
Pile driving and removal activities associated with the seawall
replacement project as outlined previously, have the potential to
disturb or displace marine mammals. Specifically, the specified
activities may result in take, in the form of Level A harassment and
Level B harassment from underwater sounds generated from pile
installation and removal. Potential takes could occur if individuals of
these species are present in the ensonified zone when these activities
are underway.
The takes from Level A and Level B harassment would be due to
potential behavioral disturbance, TTS, and PTS. No mortality is
anticipated given the nature of the activity and measures designed to
minimize the possibility of injury to marine mammals. Level A
harassment is only anticipated for harbor seals. The potential for
harassment is minimized through the construction method and
implementation of the planned mitigation measures (see Proposed
Mitigation section above).
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff
2006; HDR, Inc. 2012; Lerma 2014; ABR 2016). Most likely, individuals
will simply move away from the sound source and be temporarily
displaced from the areas of pile driving, although even this reaction
has been observed primarily only in association with impact pile
driving. The pile driving activities analyzed here are similar to, or
less impactful than, numerous other construction activities conducted
in northern California, which have taken place with no known long-term
adverse consequences from behavioral harassment. Level B harassment
will be reduced to the level of least practicable adverse impact
through use of mitigation measures described herein and, if sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the area while the activity is occurring. While
vibratory driving associated with the proposed project may produce
sound at distances of several kilometers from the project site through
the mouth of the harbor, thus intruding on some habitat, the project
site itself is located in a busy harbor and the majority of sound
fields produced by the specified activities are contained within the
harbor. Therefore, we expect that animals annoyed by project sound
would simply avoid the area and use more-preferred habitats.
In addition to the expected effects resulting from authorized Level
B harassment, we anticipate that harbor seals may sustain some limited
Level A harassment in the form of auditory injury. However, animals in
these locations that experience PTS would likely only receive slight
PTS, i.e., minor degradation of hearing capabilities within regions of
hearing that align most completely with the energy produced by pile
driving, i.e., the low-frequency region below 2 kHz, not severe hearing
impairment or impairment in the regions of greatest hearing
sensitivity. If hearing impairment occurs, it is most likely that the
affected animal would lose a few decibels in its hearing sensitivity,
which in most cases is not likely to meaningfully affect its ability to
forage and communicate with conspecifics. As described above, we expect
that marine mammals would be likely to move away from a sound source
that represents an aversive stimulus, especially at levels that would
be expected to result in PTS, given sufficient notice through use of
soft start.
The project also is not expected to have significant adverse
effects on affected marine mammals' habitat. The project activities
would not modify existing marine mammal habitat for a significant
amount of time. The activities may cause some fish to leave the area of
disturbance, thus temporarily impacting marine mammals' foraging
opportunities in a limited portion of the foraging range; but, because
of the short duration of the activities and the relatively small area
of the habitat that may be affected, the impacts to marine mammal
habitat are not expected to cause significant or long-term negative
consequences.
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 Level A harassment exposures are anticipated to result
only in slight PTS, within the lower frequencies associated with pile
driving;
The anticipated incidents of Level B harassment consist
of, at worst, temporary modifications in behavior that would not result
in fitness impacts to individuals;
The specified activity and ensonified area is very small
relative to the overall habitat ranges of all species and does not
include habitat areas of special significance (BIAs or ESA-designated
critical habitat); and
The presumed efficacy of the proposed mitigation measures
in reducing the effects of the specified activity to the level of least
practicable adverse impact.
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
[[Page 13906]]
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 presents the number of animals that could be exposed to
received noise levels that could cause Level A and Level B harassment
for the proposed activities. Our analysis shows that less than 15
percent of each affected stock could be taken by harassment. The
numbers of animals proposed to be taken for these stocks would be
considered small relative to the relevant stock's abundances even if
each estimated taking occurred to a new individual--an unlikely
scenario.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act (ESA)
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 Port District for the Aldo's Seawall Replacement
Project in Santa Cruz, CA from June 1, 2019 through May 31, 2020,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the IHA itself is available
for review in conjunction with this notice at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
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 pile
driving project. We also request comment on the potential for 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 our final decision on the request for MMPA
authorization.
On a case-by-case basis, NMFS may issue a second one-year IHA
without additional notice when (1) another year of identical or nearly
identical activities as described in the Specified Activities section
is planned or (2) the activities would not be completed by the time the
IHA expires and a second IHA would allow for completion of the
activities beyond that described in the Dates and Duration section,
provided all of the following conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA;
The request for renewal must include the following:
(1) An explanation that the activities to be conducted beyond the
initial dates either are identical to the previously analyzed
activities or include changes so minor (e.g., reduction in pile size)
that the changes do not affect the previous analyses, take estimates,
or mitigation and monitoring requirements; and
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized;
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures remain the same and appropriate,
and the original findings remain valid.
Dated: April 3, 2019.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2019-06885 Filed 4-5-19; 8:45 am]
BILLING CODE 3510-22-P