[Federal Register Volume 88, Number 213 (Monday, November 6, 2023)]
[Notices]
[Pages 76225-76241]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-24428]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
[Docket No. FWS-R7-ES-2023-0101; FXES111607MRG01-234-FF07CAMM00]
Marine Mammals; Incidental Take During Specified Activities;
Proposed Incidental Harassment Authorization for Southcentral Alaska
Stock of Northern Sea Otters in Cordova, Alaska; Draft Environmental
Assessment
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of receipt of application; proposed incidental
harassment authorization; draft environmental assessment; request for
comments.
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SUMMARY: We, the U.S. Fish and Wildlife Service, in response to a
request under the Marine Mammal Protection Act of 1972, as amended,
from the City of Cordova, Alaska, propose to authorize nonlethal
incidental take by harassment of small numbers of the Southcentral
Alaska stock of northern sea otters (Enhydra lutris kenyoni) for 1 year
from the date of issuance of the incidental harassment authorization.
The applicant has requested this authorization for take by harassment
that may result from activities associated with pile driving and marine
construction activities in Cordova, Alaska. We estimate that this
project may result in the nonlethal incidental take by harassment of up
to 82 northern sea otters from the Southcentral stock. This proposed
authorization, if finalized, will be for up to 30 takes of 5 northern
sea otters by Level A harassment and 790 takes of 77 northern sea
otters by Level B harassment. No lethal take is requested, or expected,
and no such take will be authorized.
DATES: Comments on this proposed incidental harassment authorization
and the accompanying draft environmental assessment must be received by
December 6, 2023.
ADDRESSES:
Document availability: You may view this proposed incidental
harassment authorization, the application package, supporting
information, draft environmental assessment, and the list of references
cited herein at https://www.regulations.gov under Docket No. FWS-R7-ES-
2023-0101. Alternatively, you may request these documents from the
person listed under FOR FURTHER INFORMATION CONTACT.
Comment submission: You may submit comments on the proposed
authorization by one of the following methods:
U.S. mail: Public Comments Processing, Attn: Docket No.
FWS-R7-ES-2023-0101, U.S. Fish and Wildlife Service, MS: PRB (JAO/3W),
5275 Leesburg Pike, Falls Church, VA 22041-3803.
Electronic submission: https://www.regulations.gov. Follow
the instructions for submitting comments to Docket No. FWS-R7-ES-2023-
0101.
We will post all comments at https://www.regulations.gov. You may
request that we withhold personal identifying information from public
review; however, we cannot guarantee that we will be able to do so. See
Request for Public Comments for more information.
FOR FURTHER INFORMATION CONTACT: Sierra Franks, by email at
[email protected] or by telephone at 01-800-362-5148. U.S. Fish
and Wildlife Service, MS 341, 1011 East Tudor Road, Anchorage, AK
99503. Individuals in the United States who are deaf, deafblind, hard
of hearing, or have a speech disability may dial 711 (TTY, TDD, or
TeleBraille) to access telecommunications relay services. Individuals
outside the United States should use the relay services offered within
their country to make international calls to the point-of-contact in
the United States.
SUPPLEMENTARY INFORMATION:
Background
Section 101(a)(5)(D) of the Marine Mammal Protection Act of 1972
(MMPA; 16 U.S.C. 1361 et seq.) authorizes the Secretary of the Interior
(Secretary) to allow, upon request, the incidental, but not
intentional, taking by harassment of small numbers of marine mammals in
response to requests by U.S. citizens (as defined in title 50 of the
Code of Federal Regulations (CFR) in part 18, at 50 CFR 18.27(c))
engaged in a specified activity (other than commercial fishing) in a
specified geographic region during a period of not more than 1 year.
The Secretary has delegated authority for implementation of the MMPA to
the U.S. Fish and Wildlife Service (``Service'' or ``we''). According
to the MMPA, the Service shall allow this incidental taking if we make
findings that the total of such taking for the 1-year period:
(1) is of small numbers of marine mammals of a species or stock;
(2) will have a negligible impact on such species or stocks; and
(3) will not have an unmitigable adverse impact on the availability
of these species or stocks for taking for subsistence use by Alaska
Natives.
If the requisite findings are made, we issue an authorization that
sets forth the following, where applicable:
(a) permissible methods of taking;
(b) means of effecting the least practicable adverse impact on the
species or stock and its habitat and the availability of the species or
stock for subsistence uses; and
(c) requirements for monitoring and reporting of such taking by
harassment, including, in certain circumstances, requirements for the
independent peer review of proposed monitoring plans or other research
proposals.
The term ``take'' means to harass, hunt, capture, or kill, or to
attempt to harass, hunt, capture, or kill any marine mammal.
``Harassment'' means any act of pursuit, torment, or annoyance which
(i) has the potential to injure a marine mammal or marine mammal stock
in the wild (the MMPA defines this as ``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
[[Page 76226]]
sheltering (the MMPA defines this as ``Level B harassment'').
The terms ``negligible impact'' and ``unmitigable adverse impact''
are defined in 50 CFR 18.27 (i.e., regulations governing small takes of
marine mammals incidental to specified activities) as follows:
``Negligible impact'' is 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. ``Unmitigable adverse impact''
means an impact resulting from the specified activity: (1) that is
likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by (i) causing the
marine mammals to abandon or avoid hunting areas, (ii) directly
displacing subsistence users, or (iii) placing physical barriers
between the marine mammals and the subsistence hunters; and (2) that
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
The term ``small numbers'' is also defined in 50 CFR 18.27.
However, we do not rely on that definition here as it conflates ``small
numbers'' with ``negligible impacts.'' We recognize ``small numbers''
and ``negligible impacts'' as two separate and distinct considerations
when reviewing requests for incidental harassment authorizations (IHA)
under the MMPA (see Natural Res. Def. Council, Inc. v. Evans, 232 F.
Supp. 2d 1003, 1025 (N.D. Cal. 2003)). Instead, for our small numbers
determination, we estimate the likely number of takes of marine mammals
and evaluate if that take is small relative to the size of the species
or stock.
The term ``least practicable adverse impact'' is not defined in the
MMPA or its enacting regulations. For this IHA, we ensure the least
practicable adverse impact by requiring mitigation measures that are
effective in reducing the impact of project activities, but they are
not so restrictive as to make project activities unduly burdensome or
impossible to undertake and complete.
If the requisite findings are made, we shall issue an IHA, which
may set forth the following, where applicable: (i) permissible methods
of taking; (ii) other means of effecting the least practicable impact
on the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for subsistence
uses by coastal-dwelling Alaska Natives (if applicable); and (iii)
requirements for monitoring and reporting take by harassment.
Summary of Request
On February 28, 2023, the City of Cordova (hereafter also known as
``the City'' or ``the applicant'') submitted a request to the Service
for authorization to take by Level A and Level B harassment a small
number of northern sea otters (Enhydra lutris kenyoni) (hereafter,
``sea otters'' or ``otters'' unless another species is specified) from
the Southcentral Alaska stock. The Service sent requests for additional
information on March 24, May 16, and May 30, 2023. We received updated
versions of the request on April 27, May 18, and June 8, 2023. The
Service determined the June 8, 2023, application to be adequate and
complete. The applicant expects take by harassment may occur during the
construction of replacements and improvements to the harbor facilities
in Cordova, Alaska.
Description of Specified Activities and Specified Geographic Region
The specified activity (hereafter, ``project'') will include the
installation and removal of piles and the installation of a bulkhead to
rebuild the facilities of the South Harbor in Cordova, Alaska (figure
1) between September 2023 and June 2024. The City will remove 130
existing 30-centimeter (cm) (12-inch (in)) diameter timber piles and 61
existing 30-cm (12-in) diameter steel piles and will permanently
install the following types of piles: 155 41-cm (16-in) diameter steel
piles, 140 46-cm (18-in) diameter steel piles, 30 76-cm (30-in)
diameter steel piles, and 140 steel 41-cm x 226-cm (16-in x 89-in) H
piles. Construction will also include the installation and removal of
131 61-cm (24-in) diameter temporary steel piles. Components of the
harbor that will be installed out of water include approximately 350
meters (m) (1,150 feet (ft)) of bulkhead wall supported by H piles;
main walk floats, end floats, and stall floats; 447 slips; pedestrian
gangways; other float components including bull rail, floating fenders,
mooring cleats, electricity connections, potable water service, fire
suppression waterlines, lighting, wireless connections, and hand rails;
and an uplands service area with parking lot expansion, greenspace, and
stormwater treatment capabilities. Pile-driving activities will occur
over 170 non-consecutive days for approximately 434 hours over 1 year
from date of issuance of the IHA. If the IHA is issued after the
applicant's intended start date in September 2023, its schedule for
conducting the specified activities may be adjusted accordingly. Pile
installation will be done with a combination of impact, vibratory, and
down-the-hole (DTH) drilling. Temporary piles will be removed with the
vibratory hammer. Materials and equipment will be transported via
barges, and workers will be transported to and from the barge work
platform via skiff.
Additional project details may be reviewed in the application
materials available as described under ADDRESSES or may also be
requested as described under FOR FURTHER INFORMATION CONTACT.
[[Page 76227]]
[GRAPHIC] [TIFF OMITTED] TN06NO23.060
Description of Marine Mammals in the Specified Geographic Region
Sea Otter Biology
There are three sea otter stocks in Alaska: Southeast Alaska stock,
Southcentral Alaska stock, and the Southwest Alaska stock. Only the
Southcentral Alaska stock is represented in the project area. Detailed
information about the biology of this stock can be found in the most
recent Southcentral Alaska stock assessment report (USFWS 2023), which
can be found at https://www.regulations.gov/document/FWS-R7-ES-2022-0155-0012 and was announced in the Federal Register at 88 FR 53510,
August 8, 2023.
Sea otters may be distributed anywhere within the specified project
area other than upland areas; however, they generally occur in shallow
water near the shoreline. They are most commonly observed within the
40-m (131-ft) depth contour (USFWS 2023), although they can be found in
areas with deeper water. Ocean depth is generally correlated with
distance to shore, and sea otters typically remain within 1 to 2
kilometers (km) (0.62 to 1.24 miles (mi)) of shore (Riedman and Estes
1990). They tend to be found closer to shore during storms, but venture
farther out during good weather and calm seas (Lensink 1962, Kenyon
1969).
Sea otters are nonmigratory and generally do not disperse over long
distances (Garshelis and Garshelis 1984), usually remaining within a
few kilometers of their established feeding grounds (Kenyon 1981).
Breeding males stay for all or part of the year in a breeding territory
covering up to 1 km (0.62 mi) of coastline, while adult females
maintain home ranges of approximately 8 to 16 km (5 to 10 mi), which
may include one or more male territories. Juveniles move greater
distances between resting and foraging areas (Lensink 1962, Kenyon
1969, Riedman and Estes 1990, Tinker and Estes 1996). Although sea
otters generally remain local to an area, they are capable of long-
distance travel. Sea otters in Alaska have shown daily movement
distances greater than 3 km (1.9 mi) at speeds up to 5.5 km per hour
(hr) (km/hr; 3.4 mi/hr) (Garshelis and Garshelis 1984).
Southcentral Alaska Sea Otter Stock
The Southcentral Alaska sea otter stock occurs in the center of the
sea otter range in Alaska and extends from Cape Yakataga in the east to
Cook Inlet in the west, including Prince William Sound, the eastern
Kenai Peninsula coast, and Kachemak Bay (USFWS 2023). Between 2014 and
2019, aerial surveys were conducted in three regions of the
Southcentral Alaska sea otter stock: (1) Eastern Cook Inlet, (2) Outer
Kenai Peninsula, and (3) Prince William Sound by aerial transects flown
at 91 m (298.56 ft) of altitude. The combined estimates of the three
regions resulted in approximately 21,617 (SE = 2,190) sea otters and an
average density of 1.96 sea otters per square kilometer (km\2\) for the
Southcentral Alaska stock (Esslinger et al. 2021). In aerial sea otter
abundance surveys of Prince William Sound, Weitzman and Esslinger
(2015) found a
[[Page 76228]]
density of 21.15 sea otters/km\2\ in the Orca Inlet subregion. Multiple
local sources of data (Greenwood 2022; Prince William Sound Science
Center 2022; Schinella 2022, 2023; Solstice Alaska Consulting Inc.
2022) indicate a higher density within the Cordova Harbor-approximately
20 sea otters at any given time within the 0.18 km\2\ area of the
harbor, or a density of 111.11 sea otters/km\2\. We utilized both
sources of data and applied the published density for areas outside the
harbor and the local data for areas within the harbor.
Potential Impacts of the Specified Activities on Marine Mammals
Effects of Noise on Sea Otters
We characterized ``noise'' as sound released into the environment
from human activities that exceeds ambient levels or interferes with
normal sound production or reception by sea otters. The terms
``acoustic disturbance'' or ``acoustic harassment'' are disturbances or
harassment events resulting from noise exposure. Potential effects of
noise exposure are likely to depend on the distance of the sea otter
from the sound source, the level and intensity of sound the sea otter
receives, background noise levels, noise frequency, noise duration, and
whether the noise is pulsed or continuous. The actual noise level
perceived by individual sea otters will also depend on whether the sea
otter is above or below water and atmospheric and environmental
conditions. Temporary disturbance of sea otters or localized
displacement reactions are the most likely effects to occur from noise
exposure.
Sea Otter Hearing
Pile driving and marine construction activities will fall within
the hearing range of sea otters. Controlled sound exposure trials on
southern sea otters (Enhydra lutris nereis) indicate that sea otters
can hear frequencies between 125 hertz (Hz) and 38 kilohertz (kHz) with
best sensitivity between 1.2 and 27 kHz (Ghoul and Reichmuth 2014).
Aerial and underwater audiograms for a captive adult male southern sea
otter in the presence of ambient noise suggest the sea otter's hearing
was less sensitive to high-frequency (greater than 22 kHz) and low-
frequency (less than 2 kHz) sound than terrestrial mustelids but was
similar to that of a California sea lion (Zalophus californianus).
However, the sea otter was still able to hear low-frequency sounds, and
the detection thresholds for sounds between 0.125-1 kHz were between
116-101 decibels (dB), respectively. Dominant frequencies of southern
sea otter vocalizations are between 3 and 8 kHz, with some energy
extending above 60 kHz (McShane et al. 1995, Ghoul and Reichmuth 2012).
Exposure to high levels of sound may cause changes in behavior,
masking of communications, temporary or permanent changes in hearing
sensitivity, discomfort, and injury to marine mammals. Unlike other
marine mammals, sea otters do not rely on sound to orient themselves,
locate prey, or communicate under water; therefore, masking of
communications by anthropogenic sound is less of a concern than for
other marine mammals. However, sea otters, especially mothers and pups,
do use sound for communication in air (McShane et al. 1995), and sea
otters may monitor underwater sound to avoid predators (Davis et al.
1987).
Exposure Thresholds
Underwater Sounds
Noise exposure criteria for identifying underwater noise levels
capable of causing Level A harassment to marine mammal species,
including sea otters, have been established using the same methods as
those used by the National Marine Fisheries Service (NMFS) (Southall et
al. 2019). These criteria are based on estimated levels of sound
exposure capable of causing a permanent shift in sensitivity of hearing
(i.e., a permanent threshold shift (PTS) (NMFS 2018)). PTS occurs when
noise exposure causes hairs within the inner ear system to die (Ketten
2012). Although the effects of PTS are, by definition, permanent, PTS
does not equate to total hearing loss.
Sound exposure thresholds incorporate two metrics of exposure: the
peak level of instantaneous exposure likely to cause PTS and the
cumulative sound exposure level (SELCUM) during a 24-hour
period. They also include weighting adjustments for the sensitivity of
different species to varying frequencies. PTS-based injury criteria
were developed from theoretical extrapolation of observations of
temporary threshold shifts (TTS) detected in lab settings during sound
exposure trials (Finneran 2015). Southall and colleagues (2019) predict
PTS for sea otters, which are included in the ``other marine
carnivores'' category, will occur at 232 dB peak or 203 dB
SELCUM (db SEL) for impulsive underwater sound and 219 dB
SEL for nonimpulsive (continuous) underwater sound.
Thresholds based on TTS have been used as a proxy for Level B
harassment (i.e., 70 FR 1871, January 11, 2005; 71 FR 3260, January 20,
2006; 73 FR 41318, July 18, 2008). Southall et al. (2007) derived TTS
thresholds for pinnipeds based on 212 dB peak and 171 dB SEL. Exposures
resulting in TTS in pinnipeds were found to range from 152 to 174 dB
(183 to 206 dB SEL) (Kastak et al. 2005), with a persistent TTS, if not
a PTS, after 60 seconds of 184 dB SEL (Kastak et al. 2008). Kastelein
et al. (2012) found small but statistically significant TTSs at
approximately 170 dB SEL (136 dB, 60 minutes (min)) and 178 dB SEL (148
dB, 15 min). Based on these findings, Southall et al. (2019) developed
TTS thresholds for sea otters, which are included in the ``other marine
carnivores'' category, of 188 dB SEL for impulsive sounds and 199 dB
SEL for nonimpulsive sounds.
The NMFS (2018) criteria do not identify thresholds for avoidance
of Level B harassment. For pinnipeds (seals and sea lions), NMFS has
adopted a 160-dB threshold for Level B harassment from exposure to
impulsive noise and a 120-dB threshold for continuous noise (NMFS 1998,
HESS 1999, NMFS 2018). These thresholds were developed from
observations of mysticete (baleen) whales responding to airgun
operations (e.g., Malme et al. 1983; Malme and Miles 1983; Richardson
et al. 1986, 1995) and from equating Level B harassment with noise
levels capable of causing TTS in lab settings. Southall et al. (2007,
2019) assessed behavioral response studies and found considerable
variability among pinnipeds. The authors determined that exposures
between approximately 90 to 140 dB generally do not appear to induce
strong behavioral responses from pinnipeds in water. However, they
found behavioral effects, including avoidance, become more likely in
the range between 120 to 160 dB, and most marine mammals showed some,
albeit variable, responses to sound between 140 to 180 dB. Wood et al.
(2012) adapted the approach identified in Southall et al. (2007) to
develop a probabilistic scale for marine mammal taxa at which 10
percent, 50 percent, and 90 percent of individuals exposed are assumed
to produce a behavioral response. For many marine mammals, including
pinnipeds, these response rates were set at sound pressure levels of
140, 160, and 180 dB, respectively.
We have evaluated these thresholds and determined that the Level B
threshold of 120 dB for nonimpulsive noise is not applicable to sea
otters. The 120-dB threshold is based on studies in which gray whales
(Eschrichtius robustus) were exposed to experimental playbacks of
industrial noise (Malme et
[[Page 76229]]
al. 1983, Malme and Miles 1983). During these playback studies,
southern sea otter responses to industrial noise were also monitored
(Riedman 1983, 1984). Gray whales exhibited avoidance to industrial
noise at the 120-dB threshold; however, there was no evidence of
disturbance reactions or avoidance in southern sea otters. Thus, given
the different range of frequencies to which sea otters and gray whales
are sensitive, the NMFS 120-dB threshold based on gray whale behavior
is not appropriate for predicting sea otter behavioral responses,
particularly for low-frequency sound.
Based on the lack of sea otter disturbance response or any other
reaction to the playback studies from the 1980s, as well as the absence
of a clear pattern of disturbance or avoidance behaviors attributable
to underwater sound levels up to about 160 dB resulting from low-
frequency broadband noise, we assume 120 dB is not an appropriate
behavioral response threshold for sea otters exposed to continuous
underwater noise.
Based on the best available scientific information about sea
otters, and closely related marine mammals when sea otter data are
limited, the Service has set 160 dB of received underwater sound as a
threshold for Level B harassment by disturbance for sea otters for this
proposed IHA. Exposure to unmitigated in-water noise levels between 125
Hz and 38 kHz that are greater than 160 dB-for both impulsive and
nonimpulsive sound sources-will be considered by the Service as Level B
harassment. Thresholds for Level A harassment (which entails the
potential for injury) will be 232 dB peak or 203 dB SEL for impulsive
sounds and 219 dB SEL for continuous sounds (table 1).
Airborne Sounds
The NMFS (2018) guidance neither addresses thresholds for
preventing injury or disturbance from airborne noise, nor provides
thresholds for avoidance of Level B harassment. Conveyance of
underwater noise into the air is of little concern since the effects of
pressure release and interference at the water's surface reduce
underwater noise transmission into the air. For activities that create
both in-air and underwater sounds, we will estimate take based on
parameters for underwater noise transmission. Considering sound energy
travels more efficiently through water than through air, this
estimation will also account for exposures to sea otters at the
surface.
Southall et al. (2019) have developed TTS and PTS thresholds for
other marine carnivores, which include sea otters, for airborne
impulsive and non-impulsive sounds (table 1). For project activities
that create only airborne sounds, such as pile driving on land, the
sound levels are significantly below the TTS thresholds developed by
Southall et al. 2019. NMFS has previously used ``a generalized acoustic
threshold based on received level to estimate the onset of behavioral
harassment'' (April 10, 2019, 84 FR 14314). NMFS predicts that all
other pinniped species that are not harbor seals will be behaviorally
harassed when exposed to airborne sounds above 100 dB re 20 micropascal
([micro]Pa) (84 FR 14314). Since otariid pinnipeds are the closest
available physiological and anatomical proxy for sea otters, we used
the NMFS criteria for pinniped harassment from exposure to airborne
sound to estimate take by Level B harassment from pile driving on
shore.
Table 1--Temporary Threshold Shift (TTS) and Permanent Threshold Shift (PTS) Thresholds Established by Southall et al. (2019) Through Modeling and
Extrapolation for ``Other Marine Carnivores,'' Which Include Sea Otters
[Values are weighted for other marine carnivores' hearing thresholds and given in cumulative sound exposure level (SELCUM dB re (20 [micro]Pa) in air
and SELCUM dB re (1 [micro]Pa) in water) for impulsive and nonimpulsive sounds and unweighted peak sound pressure level (SPL) in air (dB re 20
[micro]Pa) and water (dB 1[micro]Pa) (impulsive sounds only).]
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TTS PTS
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nonimpulsive impulsive nonimpulsive impulsive
------------------------------------------------------------------------------------
SELCUM SELCUM Peak SPL SELCUM SELCUM Peak SPL
--------------------------------------------------------------------------------------------------------------------------------------------------------
Air................................................................ 157 146 170 177 161 176
Water.............................................................. 199 188 226 219 203 232
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Evidence From Sea Otter Studies
Sea otters may be more resistant to the effects of sound
disturbance and human activities than other marine mammals. For
example, observers have noted no changes from southern sea otters in
regard to their presence, density, or behavior in response to
underwater sounds from industrial noise recordings at 110 dB and a
frequency range of 50 Hz to 20 kHz and airguns, even at the closest
distance of 0.5 nautical miles (<1 km or 0.6 mi) (Riedman 1983).
Southern sea otters did not respond noticeably to noise from a single
1,638 cubic centimeters (cm\3\) (100 cubic inches [in\3\]) airgun, and
no sea otter disturbance reactions were evident when a 67,006 cm\3\
(4,089 in\3\) airgun array was as close as 0.9 km (0.6 mi) to sea
otters (Riedman 1983, 1984). However, southern sea otters displayed
slight reactions to airborne engine noise (Riedman 1983). Northern sea
otters were observed to exhibit a limited response to a variety of
airborne and underwater sounds, including a warble tone, sea otter pup
calls, calls from killer whales (Orcinus orca) (which are predators to
sea otters), air horns, and an underwater noise harassment system
designed to drive marine mammals away from crude oil spills (Davis et
al. 1988). These sounds elicited reactions from northern sea otters,
including startle responses and movement away from noise sources.
However, these reactions were observed only when northern sea otters
were within 100 to 200 m (328 to 656 ft) of noise sources. Further,
northern sea otters appeared to become habituated to the noises within
2 hours or, at most, 3-4 days (Davis et al. 1988).
Noise exposure may be influenced by the amount of time sea otters
spend at the water's surface. Noise at the water's surface can be
attenuated by turbulence from wind and waves more quickly compared to
deeper water, reducing potential noise exposure (Greene and Richardson
1988, Richardson et al. 1995). Additionally, turbulence at the water's
surface limits the transference of sound from water to air. A sea otter
with its head above water will be exposed to only a small fraction of
the sound energy traveling through the water beneath it. The average
amount of time that sea otters spend above the water
[[Page 76230]]
each day while resting and grooming varies between males and females
and across seasons (Esslinger et al. 2014, Zellmer et al. 2021). For
example, female sea otters foraged for an average of 8.78 hours per day
compared to male sea otters, which foraged for an average of 7.85 hours
per day during the summer months (Esslinger et al. 2014). Male and
female sea otters spend an average of 63 to 67 percent of their day at
the surface resting and grooming during the summer months (Esslinger et
al. 2014). Few studies have evaluated foraging times during the winter
months. Garshelis et al. (1986) found that foraging times increased
from 5.1 hours per day to 16.6 hours per day in the winter; however,
Gelatt et al. (2002) did not find a significant difference in seasonal
foraging times. It is likely that seasonal variation is determined by
seasonal differences in energetic demand and the quality and
availability of prey sources (Esslinger et al. 2014). These findings
suggest that the large portion of the day sea otters spend at the
surface may help limit sea otters' exposure during noise-generating
operations.
Sea otter sensitivity to industrial activities may be influenced by
the overall level of human activity within the sea otter population's
range. In locations that lack frequent human activity, sea otters
appear to have a lower threshold for disturbance. Sea otters in Alaska
exhibited escape behaviors in response to the presence and approach of
vessels (Udevitz et al. 1995). Behaviors included diving or actively
swimming away from a vessel, entering the water from haulouts, and
disbanding groups with sea otters swimming in multiple different
directions (Udevitz et al. 1995). Sea otters in Alaska were also
observed to avoid areas with heavy boat traffic in the summer and
return to these areas during seasons with less vessel traffic
(Garshelis and Garshelis 1984). In Cook Inlet, sea otters drifting on a
tide trajectory that would have taken them within 500 m (0.3 mi) of an
active offshore drilling rig were observed to swim in order to avoid a
close approach of the drilling rig despite near-ambient noise levels
(BlueCrest 2013).
Individual sea otters in Orca Inlet will likely show a range of
responses to noise from pile-driving activities. Some sea otters will
likely dive, show startle responses, change direction of travel, or
prematurely surface. Sea otters reacting to pile-driving activities may
divert time and attention from biologically important behaviors, such
as feeding and nursing pups. Sea otter responses to disturbance can
result in energetic costs, which increases the amount of prey required
by sea otters (Barrett 2019). This increased prey consumption may
impact sea otter prey availability and cause sea otters to spend more
time foraging and less time resting (Barrett 2019). Some sea otters may
abandon the project area and return when the disturbance has ceased.
Based on the observed movement patterns of sea otters (i.e., Lensink
1962; Kenyon 1969, 1981; Garshelis and Garshelis 1984; Riedman and
Estes 1990; Tinker and Estes 1996), we expect some individuals will
respond to pile-driving activities by dispersing to nearby areas of
suitable habitat; however, other sea otters, especially territorial
adult males, are less likely to be displaced.
Consequences of Disturbance
The reactions of wildlife to disturbance can range from short-term
behavioral changes to long-term impacts that affect survival and
reproduction. When disturbed by noise, animals may respond behaviorally
(e.g., escape response) or physiologically (e.g., increased heart rate,
hormonal response) (Harms et al. 1997, Tempel and Guti[eacute]rrez
2003). Theoretically, the energy expense and associated physiological
effects from repeated disturbance could ultimately lead to reduced
survival and reproduction (Gill and Sutherland 2000, Frid and Dill
2002). For example, South American sea lions (Otaria byronia) visited
by tourists exhibited an increase in the state of alertness and a
decrease in maternal attendance and resting time on land, thereby
potentially reducing population size (Pavez et al. 2015). In another
example, killer whales that lost feeding opportunities due to boat
traffic faced a substantial (18 percent) estimated decrease in energy
intake (Williams et al. 2006). In severe cases, such disturbance
effects could have population-level consequences. For example,
increased disturbance by tourism vessels has been associated with a
decline in abundance of bottlenose dolphins (Tursiops spp.) (Bejder et
al. 2006, Lusseau et al. 2006). However, these examples evaluated
sources of disturbance that were longer term and more consistent than
the temporary and intermittent nature of the specified project
activities.
These examples illustrate direct effects on survival and
reproductive success, but disturbances can also have indirect effects.
Response to noise disturbance is considered a nonlethal stimulus that
is similar to an antipredator response (Frid and Dill 2002). Sea otters
are susceptible to predation, particularly from killer whales and
eagles, and have a well-developed antipredator response to perceived
threats. For example, the presence of a harbor seal (Phoca vitulina)
did not appear to disturb southern sea otters, but they demonstrated a
fear response in the presence of a California sea lion by actively
looking above and beneath the water (Limbaugh 1961).
Although an increase in vigilance or a flight response is
nonlethal, a tradeoff occurs between risk avoidance and energy
conservation. An animal's reactions to noise disturbance may cause
stress and direct an animal's energy away from fitness-enhancing
activities such as feeding and mating (Frid and Dill 2002, Goudie and
Jones 2004). For example, southern sea otters in areas with heavy
recreational boat traffic demonstrated changes in behavioral time
budgeting, showing decreased time resting and changes in haulout
patterns and distribution (Benham 2006, Maldini et al. 2012). Chronic
stress can also lead to weakened reflexes, lowered learning responses
(Welch and Welch 1970, van Polanen Petel et al. 2006), compromised
immune function, decreased body weight, and abnormal thyroid function
(Selye 1979).
Changes in behavior resulting from anthropogenic disturbance can
include increased agonistic interactions between individuals or
temporary or permanent abandonment of an area (Barton et al. 1998).
Additionally, the extent of previous exposure to humans (Holcomb et al.
2009), the type of disturbance (Andersen et al. 2012), and the age or
sex of the individuals (Shaughnessy et al. 2008, Holcomb et al. 2009)
may influence the type and extent of response in individual sea otters.
Vessel Activities
Vessel collisions with marine mammals can result in death or
serious injury. Wounds resulting from vessel strike may include massive
trauma, hemorrhaging, broken bones, or propeller lacerations (Knowlton
and Kraus 2001). An animal may be harmed by a vessel when the vessel
runs over the animal at the surface, the animal hits the bottom of a
vessel while the animal is surfacing, or the animal is cut by a
vessel's propeller.
Vessel strike has been documented as a cause of death across all
three stocks of northern sea otters in Alaska. Since 2002, the Service
has conducted 1,433 sea otter necropsies to determine cause of death,
disease incidence, and the general health status of sea otters in
Alaska. Vessel strike or blunt trauma was identified as a definitive or
[[Page 76231]]
presumptive cause of death in 65 cases (4 percent) (USFWS 2020). In
most of these cases, trauma was determined to be the ultimate cause of
death; however, there was a contributing factor, such as disease or
biotoxin exposure, which incapacitated the sea otter and made it more
vulnerable to vessel strike (USFWS 2023).
Vessel speed influences the likelihood of vessel strikes involving
sea otters. The probability of death or serious injury to a marine
mammal increases as vessel speed increases (Laist et al. 2001,
Vanderlaan and Taggart 2007). Sea otters spend a considerable portion
of their time at the water's surface (Esslinger et al. 2014). They are
typically visually aware of approaching vessels and can move away if a
vessel is not traveling too quickly. Mitigation measures to be applied
to vessel operations to prevent collisions or interactions are included
below in the proposed authorization portion of this document under
Avoidance and Minimization.
Sea otters exhibit behavioral flexibility in response to vessels,
and their responses may be influenced by the intensity and duration of
the vessel's activity. As noted above, sea otter populations in Alaska
were observed to avoid areas with heavy vessel traffic but return to
those same areas during seasons with less vessel traffic (Garshelis and
Garshelis 1984). Sea otters have also shown signs of disturbance or
escape behaviors in response to the presence and approach of survey
vessels, including sea otters diving and/or actively swimming away from
a vessel, sea otters on haulouts entering the water, and groups of sea
otters disbanding and swimming in multiple different directions
(Udevitz et al. 1995).
Additionally, sea otter responses to vessels may be influenced by
the sea otter's previous experience with vessels. Groups of southern
sea otters in two locations in California showed markedly different
responses to kayakers approaching to within specific distances,
suggesting a different level of tolerance between the groups (Gunvalson
2011). Benham (2006) found evidence that the sea otters exposed to high
levels of recreational activity may have become more tolerant than
individuals in less disturbed areas. Sea otters off the California
coast showed only mild interest in vessels passing within hundreds of
meters and appeared to have habituated to vessel traffic (Riedman 1983,
Curland 1997). These findings indicate that sea otters may adjust their
responses to vessel activities depending on the level of activity.
Vessel activity during the project includes the transit of two barges
for materials and construction, both of which will remain on site,
mostly stationary, to support the work; additionally, a skiff will be
used during the project for transporting workers short distances to
support construction activities. Vessels will not be used extensively
or over a long duration during the planned work; therefore, we do not
anticipate that sea otters will experience changes in behavior
indicative of tolerance or habituation.
Effects on Sea Otter Habitat and Prey
Physical and biological features of habitat essential to the
conservation of sea otters include the benthic invertebrates that sea
otters eat and the shallow rocky areas and kelp beds that provide cover
from predators. Sea otter habitat in the project area includes coastal
areas within the 40-m (131-ft) depth contour where high densities of
sea otters have been detected.
Industrial activities, such as pile driving, may generate in-water
noise at levels that can temporarily displace sea otters from important
habitat and impact sea otter prey species. The primary prey species for
sea otters are sea urchins (Strongylocentrotus spp. and Mesocentrotus
spp.), abalone (Haliotis spp.), clams (e.g., Clinocardium nuttallii,
Leukoma staminea, and Saxidomus gigantea), mussels (Mytilus spp.),
crabs (e.g., Metacarcinus magister, Pugettia spp., Telemessus
cheiragonus, and Cancer spp.), and squid (Loligo spp.) (Tinker and
Estes 1996, LaRoche et al. 2021). When preferred prey are scarce, sea
otters will also eat kelp, slow-moving benthic fishes, sea cucumbers
(e.g., Apostichopus californicus), egg cases of rays, turban snails
(Tegula spp.), octopuses (e.g., Octopus spp.), barnacles (Balanus
spp.), sea stars (e.g., Pycnopodia helianthoides), scallops (e.g.,
Patinopecten caurinus), rock oysters (Saccostrea spp.), worms (e.g.,
Eudistylia spp.), and chitons (e.g., Mopalia spp.) (Riedman and Estes
1990, Davis and Bodkin 2021).
Several studies have addressed the effects of noise on
invertebrates (Tidau and Briffa 2016, Carroll et al. 2017). Behavioral
changes, such as an increase in lobster (Homarus americanus) feeding
levels (Payne et al. 2007), an increase in avoidance behavior by wild-
caught captive reef squid (Sepioteuthis australis) (Fewtrell and
McCauley 2012), and deeper digging by razor clams (Sinonovacula
constricta) (Peng et al. 2016) have been observed following
experimental exposures to sound. Physical changes have also been
observed in response to increased sound levels, including changes in
serum biochemistry and hepatopancreatic cells in lobsters (Payne et al.
2007) and long-term damage to the statocysts required for hearing in
several cephalopod species (Andr[eacute] et al. 2011, Sol[eacute] et
al. 2013). De Soto et al. (2013) found impaired embryonic development
in scallop (Pecten novaezelandiae) larvae when exposed to 160 dB.
Christian et al. (2003) noted a reduction in the speed of egg
development of bottom-dwelling crabs following exposure to noise;
however, the sound level (221 dB at 2 m or 6.6 ft) was far higher than
the planned project activities will produce. Industrial noise can also
impact larval settlement by masking the natural acoustic settlement
cues for crustaceans and fish (Pine et al. 2012, Simpson et al. 2016,
Tidau and Briffa 2016).
While these studies provide evidence of deleterious effects to
invertebrates as a result of increased sound levels, Carroll et al.
(2017) caution that there is a wide disparity between results obtained
in field and laboratory settings. In experimental settings, changes
were observed only when animals were housed in enclosed tanks, and many
were exposed to prolonged bouts of continuous, pure tones. We would not
expect similar results in open marine conditions. It is unlikely that
noises generated by project activities will have any lasting effect on
sea otter prey given the short-term duration of sounds produced by each
component of the planned work.
Noise-generating activities that interact with the seabed can
produce vibrations, resulting in the disturbance of sediment and
increased turbidity in the water. Although turbidity is likely to have
little impact on sea otters and prey species (Todd et al. 2015), there
may be some impacts from vibrations and increased sedimentation. For
example, mussels (Mytilus edulis) exhibited changes in valve gape and
oxygen demand, and hermit crabs (Pagurus bernhardus) exhibited limited
behavioral changes in response to vibrations caused by pile driving
(Roberts et al. 2016). Increased sedimentation is likely to reduce sea
otter visibility, which may result in reduced foraging efficiency and a
potential shift to less-preferred prey species. These outcomes may
cause sea otters to spend more energy on foraging or processing the
prey items; however, the impacts of a change in energy expenditure are
not likely seen at the population level (Newsome et al. 2015).
Additionally, the benthic invertebrates may be impacted by increased
sedimentation, resulting in higher
[[Page 76232]]
abundances of opportunistic species that recover quickly from
industrial activities that increase sedimentation (Kotta et al. 2009).
Although sea otter foraging could be impacted by industrial activities
that cause vibrations and increased sedimentation, it is more likely
that sea otters would be temporarily displaced from the project area
due to impacts from noise rather than vibrations and sedimentation.
Potential Impacts of the Specified Activities on Subsistence Uses
The planned specified activities will occur near marine subsistence
harvest areas used by Alaska Natives from Cordova and the surrounding
areas. Since 2013, there have been 914 sea otters harvested by hunters
from the Cordova area, and most of those were taken prior to 2016. From
2018 through 2022, 236 sea otters were harvested from the Cordova area.
The planned project would occur within the Cordova city limits,
where firearm use is prohibited. The area potentially affected by the
planned project does not significantly overlap with current subsistence
harvest areas. Construction activities will not preclude access to
hunting areas or interfere in any way with individuals wishing to hunt.
Despite no conflict with subsistence use being anticipated, the Service
will notify potentially affected communities and stakeholders of the
public comment period on this proposed IHA so they have an opportunity
to share any questions, concerns, or potential conflicts regarding
subsistence use in those areas. If any conflicts are identified in the
future, the applicant will develop a plan of cooperation specifying the
steps necessary to minimize any effects the project may have on
subsistence harvest.
Estimated Take
Definitions of Incidental Take Under the Marine Mammal Protection Act
Below we provide definitions of three potential types of take of
sea otters. The Service does not anticipate and is not authorizing
lethal take as a part of this proposed IHA; however, the definitions of
these take types are provided for context and background:
Lethal Take--Human activity may result in biologically significant
impacts to sea otters. In the most serious interactions, human actions
can result in mortality of sea otters.
Level A Harassment--Human activity may result in the injury of sea
otters. Level A harassment, for nonmilitary readiness activities, is
defined as any act of pursuit, torment, or annoyance that has the
potential to injure a marine mammal or marine mammal stock in the wild.
Level B Harassment--Level B Harassment for nonmilitary readiness
activities means any act of pursuit, torment, or annoyance that 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, feeding, or sheltering.
Changes in behavior that disrupt biologically significant behaviors or
activities for the affected animal are indicative of take by Level B
harassment under the MMPA.
The Service has identified the following sea otter behaviors as
indicative of possible Level B harassment:
Swimming away at a fast pace on belly (i.e., porpoising);
Repeatedly raising the head vertically above the water to
get a better view (spyhopping) while apparently agitated or while
swimming away;
In the case of a pup, repeatedly spyhopping while hiding
behind and holding onto its mother's head;
Abandoning prey or feeding area;
Ceasing to nurse and/or rest (applies to dependent pups);
Ceasing to rest (applies to independent animals);
Ceasing to use movement corridors;
Ceasing mating behaviors;
Shifting/jostling/agitation in a raft so that the raft
disperses;
Sudden diving of an entire raft; or
Flushing animals off a haulout.
This list is not meant to encompass all possible behaviors; other
behavioral responses may equate to take by Level B harassment.
Relatively minor changes in behavior such as increased vigilance or a
short-term change in direction of travel are not likely to disrupt
biologically important behavioral patterns, and the Service does not
view such minor changes in behavior as indicative of a take by Level B
harassment.
Calculating Take
We assumed all animals exposed to underwater sound levels that meet
the acoustic exposure criteria defined above in Exposure Thresholds
will experience take by Level A or Level B harassment due to exposure
to underwater noise. Likewise, we assumed that all animals exposed to
airborne sound levels that meet the acoustic exposure criteria in
Exposure Thresholds will experience take by Level B harassment due to
exposure to in-air noise. Spatially explicit zones of ensonification
were established around the planned construction location to estimate
the number of otters that may be exposed to these sound levels. We
determined the number of otters present in the ensonification zones
using density information generated by Weitzman and Esslinger (2015),
as well as local sources of data that indicated a higher density of sea
otters within the harbor (Greenwood 2022; Prince William Sound Science
Center 2022; Schinella 2022, 2023; Solstice Alaska Consulting Inc.
2022).
The project can be divided into five major components: DTH pile
driving, vibratory pile driving, impact pile driving, skiff use to
support construction, and pile driving on land. Each of these
components will generate a different type of noise. Vibratory pile
driving and the use of skiffs will produce nonimpulsive or continuous
noise; impact pile driving will produce impulsive noise; and DTH pile
driving is considered to produce both impulsive and continuous noise
(NMFS 2020).
The level of sound anticipated from each project component was
established using recorded data from several sources listed in tables 2
through 7. We used the NMFS Technical Guidance and User Spreadsheet
(NMFS 2018, 2020) to determine the distance at which sound levels would
attenuate to Level A harassment thresholds, and empirical data from the
proxy projects were used to determine the distance at which sound
levels would attenuate to Level B harassment thresholds (table 1). The
weighting factor adjustment included in the NMFS user spreadsheet
accounts for sounds created in portions of an organism's hearing range
where they have less sensitivity. We used the weighting factor
adjustment for otariid pinnipeds as they are the closest available
physiological and anatomical proxy for sea otters. The spreadsheet also
incorporates a transmission loss coefficient, which accounts for the
reduction in sound level outward from a sound source. We used the NMFS-
recommended transmission loss coefficient of 15 for coastal pile-
driving activities to indicate practical spread (NMFS 2020) to
determine the distance at which sound levels attenuate to 160 dB re 1
[micro]Pa. Due to limited data of underwater sound pressure levels from
DTH pile driving as well as differences in how PTS and TTS thresholds
are calculated, the resultant Level A isopleths for DTH pile driving
are larger than the Level B isopleths.
[[Page 76233]]
Table 2--Summary of Sound Level, Timing of Sound Production, Distance From Sound Source to Below Level A Harassment and Level B Harassment Thresholds,
Days of Impact, Sea Otters in Level A and Level B Harassment Ensonification Area, and Total Otters Expected To Be Harassed Through Behavioral
Disturbance by Vibratory Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
30 to 61-cm (12- 30 to 61-cm (12-
in to 24-in) in to 24-in) 61-cm (24-inch) 61-cm (24-inch) 41-cm (16-in) 46-cm (18-in) 76-cm (30-in)
Pile size existing timber existing steel template template removal permanent pile permanent pile permanent pile
pile removal pile removal installation installation installation installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total number of piles........ 130............. 61.............. 61.............. 61.............. 155............ 70............. 30.
----------------------------------------------------------------------------------------
Sound level.................. 162 dB re 1 161 dB re 1 [micro]Pa at 10 m (RMS) 161.9 dB re 1
[micro]Pa at 10 [micro]Pa at
m (RMS). 10 m (RMS).
----------------------------------------------------------------------------------------
Source....................... NMFS 2023....... NAVFAC\a\ 2013, 2015 Denes et al.
2016.
----------------------------------------------------------------------------------------
Timing per pile.............. 10 minutes/pile. 10 minutes/pile. 10 minutes/pile. 10 minutes/pile. 15 minutes/pile 20 minutes/pile 30 minutes/
pile.
Maximum number of piles per 25.............. 25.............. 6............... 10.............. 10............. 10............. 6.
day.
Maximum number of days of 6............... 3............... 11.............. 7............... 16............. 7.............. 5.
activity.
--------------------------------------------------------------------------------------------------------------------------
Sea otter density............ 111.11 sea otters/km\2\
--------------------------------------------------------------------------------------------------------------------------
Distance to below Level A 0.9 meters...... 0.8 meters...... 0.4 meters...... 0.4 meters...... 0.5 meters..... 0.7 meters..... 0.7 meters.
harassment threshold.
Level A area (km\2\)......... 0.0000.......... 0.0000.......... 0.0000.......... 0.0000.......... 0.0000......... 0.0000......... 0.0000.
Potential sea otters affected 0............... 0............... 0............... 0............... 0.............. 0.............. 0.
by Level A sound per day.
Potential sea otters affected 0............... 0............... 0............... 0............... 0.............. 0.............. 0.
by Level A sound per day
(rounded).
Total potential Level A 0............... 0............... 0............... 0............... 0.............. 0.............. 0.
harassment events.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance to below Level B 14 meters....... 12 meters....... 12 meters....... 12 meters....... 12 meters...... 12 meters...... 13 meters.
harassment threshold.
Level B area (km\2\)......... 0.0003.......... 0.0002.......... 0.0002.......... 0.0002.......... 0.0002......... 0.0002......... 0.0002.
Potential sea otters affected 0.0333.......... 0.0222.......... 0.0222.......... 0.0222.......... 0.0222......... 0.0222......... 0.0222.
by Level B sound per day.
Potential sea otters affected 1............... 1............... 1............... 1............... 1.............. 1.............. 1.
by Level B sound per day
(rounded).
Total potential Level B 6............... 3............... 11.............. 7............... 16............. 7.............. 5.
harassment events.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Naval Facilities Engineering Command.
Table 3--Summary of Sound Level, Timing of Sound Production, Distance From Sound Source to Below Level A
Harassment Thresholds, Days of Impact, Sea Otters in Level A Harassment Ensonification Area, and Total Otters
Expected To Be Taken by Level A Harassment by Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
41-cm (16-in) permanent 46-cm (18-in) permanent 76-cm (30-in) permanent
Pile size pile installation pile installation pile installation
----------------------------------------------------------------------------------------------------------------
Total number of piles................ 73..................... 35..................... 20.
Sound level.......................... 168.3 dB (SEL)/181.1 dB 168.3 dB (SEL)/181.1 dB 177 dB (SEL)/190 dB
(RMS)/192.8 dB (peak) (RMS)/192.8 dB (peak) (RMS)/210 dB (peak) re
re 1 [micro]Pa at 10 m. re 1 [micro]Pa at 10 m. 1 [micro]Pa at 10 m.
--------------------------------------------------
Source............................... Denes et al. 2016 NMFS 2023.
--------------------------------------------------
Timing per pile...................... 20 minutes/pile; 240 20 minutes/pile; 240 20 minutes/pile; 360
strikes/pile. strikes/pile. strikes/pile.
Maximum number piles per day......... 6...................... 6...................... 6.
Maximum number of days of activity... 13..................... 6...................... 4.
--------------------------------------------------------------------------
Sea otter density.................... 111.11 sea otters/km\2\
--------------------------------------------------------------------------
Distance to below Level A harassment 5.2 meters............. 5.2 meters............. 25.9 meters.
threshold.
Total Level A area (km\2\)........... 0.0001................. 0.0001................. 0.0021.
Level A area (km\2\) after excluding 0...................... 0...................... 0.0018.
10-m shutdown zone (0.0003 km\2\).
Potential sea otters affected by 0...................... 0...................... 0.2000.
Level A sound per day.
Potential sea otters affected by 0...................... 0...................... 1.
Level A sound per day (rounded).
Total potential Level A harassment 0...................... 0...................... 4.
events.
----------------------------------------------------------------------------------------------------------------
[[Page 76234]]
Table 4--Summary of Sound Level, Timing of Sound Production, Distance From Sound Source to Below Level B
Harassment Thresholds, Days of Impact, Sea Otters in Level B Ensonification Area, and Total Otters Expected To
Be Taken by Level B Harassment by Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
41-cm (16-in) permanent 46-cm (18-in) permanent 76-cm (30-in) permanent
Pile size pile installation pile installation pile installation
----------------------------------------------------------------------------------------------------------------
Total number of piles................ 73..................... 35..................... 20.
Sound level.......................... 168.3 dB (SEL)/181.1 dB 168.3 dB (SEL)/181.1 dB 177 dB (SEL)/190 dB
(RMS)/192.8 dB (peak) (RMS)/192.8 dB (peak) (RMS)/210 dB (peak) re
re 1 [micro]Pa at 10 m. re 1 [micro]Pa at 10 m. 1 [micro]Pa at 10 m.
--------------------------------------------------
Source............................... Denes et al. 2016 NMFS 2023.
--------------------------------------------------
Timing per pile...................... 20 minutes/pile; 240 20 minutes/pile; 240 20 minutes/pile; 360
strikes/pile. strikes/pile. strikes/pile.
Maximum number piles per day......... 6...................... 6...................... 6.
Maximum number of days of activity... 13..................... 6...................... 4.
Distance to below Level B harassment 255 meters............. 255 meters............. 1,000 meters.
threshold \a\.
Total Level B area (km\2\)........... 0.2038................. 0.2038................. 0.3137.
Level B area (km\2\) within harbor... 0.18................... 0.18................... 0.18.
--------------------------------------------------------------------------
Sea otter density inside harbor...... 111.11 sea otters/km\2\
--------------------------------------------------
Potential sea otters affected by 19.9998................ 19.9998................ 19.9998.
Level B sound per day within harbor.
Potential sea otters affected by 20..................... 20..................... 20.
Level B sound per day within harbor
(rounded).
Potential Level B harassment events 260.................... 120.................... 80.
within harbor.
Level B area (km\2\) outside harbor.. 0.0238................. 0.0238................. 0.1337.
--------------------------------------------------------------------------
Sea otter density outside harbor..... 21.15 sea otters/km\2\
--------------------------------------------------
Potential sea otters affected by 0.5034................. 0.5034................. 2.8278.
Level B sound per day outside harbor.
Potential sea otters affected by 1...................... 1...................... 3.
Level B sound per day outside harbor
(rounded).
Potential Level B harassment events 13..................... 6...................... 12.
outside harbor.
Total potential Level B harassment 273.................... 126.................... 92.
events.
----------------------------------------------------------------------------------------------------------------
Table 5--Summary of Sound Level, Timing of Sound Production, Distance From Sound Source to Below Level A
Harassment and Level B Harassment Thresholds, Days of Impact, Sea Otters in Level A and Level B Harassment
Ensonification Area, and Total Otters Expected To Be Harassed Through Behavioral Disturbance by Down-the-Hole
Pile Driving
----------------------------------------------------------------------------------------------------------------
41-cm (16-in) 46-cm (18-in)
Pile size permanent pile permanent pile 76-cm (30-in) permanent
installation installation pile installation
----------------------------------------------------------------------------------------------------------------
Total number of piles................ 50..................... 20..................... 16.
--------------------------------------------------
Sound level.......................... 159 dB (SEL)/167 dB (RMS) re 1 [mu]Pa at 10 m 164 dB (SEL)/174 dB
(RMS) re 1 [mu]Pa at
10 m.
--------------------------------------------------
Source............................... Heyvaert and Reyff 2021 Reyff and Heyvaert
2019, Reyff 2020,
Denes et al. 2019.
--------------------------------------------------
Timing per pile...................... 75 minutes/pile........ 75 minutes/pile........ 75 minutes/pile.
Maximum number piles per day......... 4...................... 4...................... 4.
Maximum number of days of activity... 13..................... 5...................... 4.
--------------------------------------------------------------------------
Sea otter density.................... 111.11 sea otters/km\2\
--------------------------------------------------------------------------
Distance to below Level A harassment 35.2 meters............ 35.2 meters............ 67.1 meters.
threshold.
Total Level A area (km\2\)........... 0.0039................. 0.0039................. 0.0141.
Level A area (km\2\) after excluding 0.0036................. 0.0036................. 0.0138.
10-m shutdown zone (0.0003 km\2\).
Potential sea otters affected by 0.4000................. 0.4000................. 1.5333.
Level A sound per day.
Potential sea otters affected by 1...................... 1...................... 2.
Level A sound per day (rounded).
Total potential Level A harassment 13..................... 5...................... 8.
events.
Distance to below Level B harassment 29 meters.............. 29 meters.............. 86 meters.
threshold \a\.
Level B area (km\2\)................. 0...................... 0...................... 0.0091.
Potential sea otters affected by 0...................... 0...................... 1.0111.
Level B sound per day.
Potential sea otters affected by 0...................... 0...................... 2.
Level B sound per day (rounded).
[[Page 76235]]
Total potential Level B harassment 0...................... 0...................... 8.
events.
----------------------------------------------------------------------------------------------------------------
\a\ Due to differences in how PTS and TTS thresholds are calculated, the Level A isopleths are larger than the
Level B isopleths.
Table 6--Summary of Sound Level, Timing of Sound Production, Distance
From Sound Source to Below Level A Harassment and Level B Harassment
Thresholds, Days of Impact, Sea Otters in Level A and Level B Harassment
Ensonification Area, and Total Otters Expected To Be Harassed Through
Behavioral Disturbance by Use of a Skiff
------------------------------------------------------------------------
Sound source Worker transit skiff
------------------------------------------------------------------------
Sound level................................ 182 dB (RMS) re 1 [mu]Pa at
0.9 m.
Source..................................... Kipple and Gabriele 2007.
Number of days of vessel use............... 170.
Sea otter density.......................... 111.11 sea otters/km\2\.
Distance to below Level A harassment 0 meters.
threshold.
Level A area (km\2\)....................... 0.
Potential sea otters affected by Level A 0.
sound per day.
Potential sea otters affected by Level A 0.
sound per day (rounded).
Total potential Level A harassment events.. 0.
Distance to below Level B harassment 26.4 meters.
threshold.
Total Level B area (km\2\)................. 0.007.
Level B area after excluding 10-m shutdown 0.0067.
zone (0.0003 km\2\).
Potential sea otters affected by Level B 0.7444.
sound per day.
Potential sea otters affected by Level B 1.
sound per day (rounded).
Total potential Level B harassment events.. 170.
------------------------------------------------------------------------
Table 7--Summary of Sound Level, Timing of Sound Production, Distance From Sound Source to Below Level B
Harassment Thresholds, Days of Impact, Sea Otters in Level B Harassment Ensonification Area, and Total Otters
Expected To Be Harassed Through Behavioral Disturbance by In-Air Sound
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving on
Sound source shore Impact pile driving on shore
----------------------------------------------------------------------------------------------------------------
Sound level....................................... 103.2 dB re 20 [mu]Pa at 15 m 101 dB 20 [mu]Pa at 15 m
(RMS). (RMS).
Source............................................ Laughlin 2010................ Ghebreghzabiher 2017.
Maximum number of days of activity................ 45........................... 21.
-------------------------------------------------------------
Sea otter density................................. 111.11 sea otters/km.\2\
-------------------------------------------------------------
Distance to below Level B harassment threshold.... 22 meters.................... 17 meters.
Total Level B area (km\2\)........................ 0.0015....................... 0.0009.
Level B area after excluding 10-m shutdown zone 0.0012....................... 0.0006.
(0.0003 km\2\).
Potential sea otters affected by Level B sound per 0.1333....................... 0.0667.
day.
Potential sea otters affected by Level B sound per 1............................ 1.
day (rounded).
Total potential Level B harassment events......... 45........................... 21.
----------------------------------------------------------------------------------------------------------------
Sound levels for all underwater sound sources are unweighted and
given in dB re 1 [mu]Pa; sound levels for airborne sound sources are
unweighted and given in dB re 20 [mu]Pa. Nonimpulsive sounds are in the
form of mean maximum root mean square (RMS) sound pressure level (SPL)
as it is more conservative than cumulative sound exposure level (SEL)
or peak SPL for these activities. Impulsive sound sources are in the
form of SEL for a single strike.
To determine the number of sea otters that may experience in-water
sounds >160 dB re 1[mu]Pa due to pile driving, we multiplied the area
ensonified to >160 dB re 1[mu]Pa outside Cordova Harbor by the density
of animals (21.15 sea otters/km\2\) derived from surveys conducted of
Orca Inlet (Weitzman and Esslinger 2015), whereas the area ensonified
to >160 dB re 1[mu]Pa within Cordova Harbor was multiplied by the
density derived from local knowledge (111.11 sea otters/km\2\;
Greenwood 2022; Prince William Sound Science Center 2022; Schinella
2022, 2023; Solstice Alaska Consulting Inc. 2022). We applied the same
methodology to determine the number of sea otters that may experience
sounds capable of causing PTS. Similarly, to determine the number of
sea otters that may experience airborne construction sounds >100 dB re
20 [mu]Pa due to pile driving, we multiplied the area ensonified to
>100 dB re 20 [mu]Pa by the density of sea otters within the harbor
(111.11 sea otters/km\2\; Greenwood 2022; Prince William Sound Science
Center 2022; Schinella 2022, 2023; Solstice Alaska Consulting Inc.
2022). The number of sea otters expected to be exposed to such sound
levels can be found in tables 2 through 7. To calculate the underwater
area ensonified for most types of pile-driving activity, we used
[pi]r\2\. Given the numerous harbor floats and the number of piles
being removed and installed, it was not feasible to calculate the
actual area of water
[[Page 76236]]
ensonified for most activities, so the area of a circle was used for a
conservative estimate for pile driving activities where the ensonified
area is entirely within the harbor. Likewise, to calculate the area
ensonified by pile-driving activities on shore, we used [pi]r\2\. For
the Level B underwater area ensonified by impact pile driving 76-cm
(30-in) piles, we used ArcGIS Pro to map the zones and calculate the
area of the water ensonified, since it is the largest zone and extends
beyond the harbor. The applicant proposed a universal 10-m (33-ft)
shutdown zone for all project activities so that area was subtracted
from all calculated areas when estimating take.
The area ensonified by the worker transit skiff was estimated by
multiplying the vessel's anticipated daily track length by twice the
160 dB radius plus [pi]r\2\ to account for the rounded ends of the
track line. It was estimated that the distance of each trip would be no
more than 91.44 m (300 ft).
We assumed that the different types of activities would occur
sequentially and that the total number of days of work would equal the
sum of the number of days required to complete each type of activity.
While it is possible that on some days more than one type of activity
will take place, which would reduce the number of days of exposure
within a year, we cannot know this information in advance. As such, the
estimated number of days and, therefore, exposures per year is the
maximum possible for the planned work. Where the number of exposures
expected per day was zero to three or more decimal places (i.e.,
<0.00X), the number of exposures per day was assumed to be zero.
In order to minimize exposure of sea otters to sounds above Level A
harassment thresholds, the applicant will implement shutdown zones
ranging from 10 to 100 m (33 to 328 ft), based on the pile size and
type of pile driving or construction activity, where operations will
cease should a sea otter enter or approach the specified zone. Soft-
start and zone clearance prior to startup will also limit the exposure
of sea otters to sound levels that could cause PTS. However, the City
of Cordova has requested, and the Service proposes to authorize, small
numbers of take by Level A harassment during impact pile driving and
DTH drilling.
Critical Assumptions
We estimate that 790 takes of 77 sea otters by Level B harassment
and 30 takes of 5 sea otters by Level A harassment may occur due to the
City's planned harbor construction activities. In order to conduct this
analysis and estimate the potential amount of take by harassment,
several critical assumptions were made.
Level B harassment is equated herein with behavioral responses that
indicate harassment or disturbance. There is likely a portion of
animals that respond in ways that indicate some level of disturbance
but do not experience significant biological consequences.
We used the sea otter density for Orca Inlet from surveys and
analyses conducted by Weitzman and Esslinger (2015) for areas
ensonified outside Cordova Harbor. Methods and assumptions for these
surveys can be found in the original publication.
Multiple local sources (Greenwood 2022; Prince William Sound
Science Center 2022; Schinella 2022, 2023; Solstice Alaska Consulting
Inc. 2022) indicated a higher density within the Cordova Harbor--
approximately 20 sea otters at any given time within the 0.18 km\2\
area of the harbor, or a density of 111.11 sea otters/km\2\. We used
this density to estimate take for areas ensonified within the harbor.
We used sound source verification from recent pile-driving
activities in a number of locations within and beyond Alaska to
generate sound level estimates for construction activities.
Environmental conditions in these locations, including water depth,
substrate, and ambient sound levels, are similar to those in the
project location, but not identical. Further, estimation of underwater
ensonification zones were based on sound attenuation models using a
practical spreading loss model; estimation of in-air ensonification
zones were based on sound attenuation models using a spherical
spreading loss model. These factors may lead to actual sound values
differing slightly from those estimated here.
Finally, the in-water pile-driving activities described here will
also create in-air noise. Because sea otters spend over half of their
day with their heads above water (Esslinger et al. 2014), they will be
exposed to increased in-air noise from construction equipment. However,
we have calculated Level B harassment with the assumption that an
individual may be harassed only one time per 24-hour period, and
underwater sound levels will be more disturbing and extend farther than
in-air noise. Thus, while sea otters may be disturbed by noise both in
air and underwater, we have relied on the more conservative underwater
estimates.
Sum of Harassment From All Sources
The applicant plans to conduct pile driving and marine construction
activities in Cordova, Alaska, over the course of a year from the date
of issuance of the IHA. A summary of total estimated take during the
project, by source, is provided in table 8.
Table 8--Total Estimated Takes by Source of Level A and Level B Harassment of Sea Otters
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sea otters Total takes of Sea otters Total takes of
Number of exposed per day sea otters by exposed per day sea otters by
Source days of to Level A Level A to Level B Level B
activity harassment harassment harassment harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory drilling:
30-to-61-cm (12-in-to-24-in) existing timber pile removal.... 6 0 0 1 6
30-to-61-cm (12-in-to-24-in) existing steel pile removal..... 3 0 0 1 3
61-cm (24-in) template installation.......................... 11 0 0 1 11
61-cm (24-in) template removal............................... 7 0 0 1 7
41-cm (16-in) permanent pile installation.................... 16 0 0 1 16
46-cm (18-in) permanent pile installation.................... 7 0 0 1 7
76-cm (30-in) permanent pile installation.................... 5 0 0 1 5
Impact drilling:
41-cm (16-in) permanent pile installation.................... 13 0 0 21 273
46-cm (18-in) permanent pile installation.................... 6 0 0 21 126
76-cm (30-in) permanent pile installation.................... 4 1 4 23 92
Down-the-hole drilling:
41-cm (16-in) permanent pile installation.................... 13 1 13 0 0
46-cm (18-in) permanent pile installation.................... 5 1 5 0 0
76-cm (30-in) permanent pile installation.................... 4 2 8 2 8
Skiff use:
Worker transit skiff......................................... 170 0 0 1 170
[[Page 76237]]
In-air Sound:
Vibratory pile driving on shore.............................. 45 0 0 1 45
Impact pile driving on shore................................. 21 0 0 1 21
--------------------------------------------------------------------------------------
Totals................................................... 336 5 30 77 790
--------------------------------------------------------------------------------------------------------------------------------------------------------
Over the course of the project, we estimate 790 instances of take
by Level B harassment of 77 northern sea otters from the Southcentral
Alaska stock due to behavioral responses of TTS associated with noise
exposure. Although multiple instances of Level B harassment of
individual sea otters are possible, these events are unlikely to have
significant consequences for the health, reproduction, or survival of
affected animals, and therefore would not rise to the level of an
injury or Level A harassment.
The use of soft-start procedures, zone clearance prior to startup,
and shutdown zones is likely to decrease both the number of sea otters
exposed to sounds above Level A harassment thresholds and the exposure
time of any sea otters venturing into a Level A harassment zone. This
reduces the likelihood of losses of hearing sensitivity that might
impact the health, reproduction, or survival of affected animals.
Despite the implementation of mitigation measures, it is anticipated
that some sea otters will experience Level A harassment via exposure to
underwater sounds above threshold criteria during impact and DTH pile-
driving activities. Due to sea otters' small body size and low profile
in the water, as well as the relatively large size of the Level A
harassment zone associated with these activities, we anticipate that
sea otters will at times avoid detection before entering Level A
harassment zones for those activities. We anticipate that protected
species observers (PSOs) will be able to reliably detect and prevent
take by Level A harassment of sea otters up to 10 m (33 ft) away;
conversely, we anticipate that at distances greater than 10 m, sea
otters will at times avoid detection. Throughout the project, we
estimate 30 instances of take by Level A harassment of 5 sea otters.
Determinations and Findings
Sea otters exposed to sound from the specified activities are
likely to respond with temporary behavioral modification or
displacement. The specified activities could temporarily interrupt the
feeding, resting, and movement of sea otters. Because activities will
occur during a limited amount of time and in a localized region, the
impacts associated with the project are likewise temporary and
localized. The anticipated effects are short-term behavioral reactions
and displacement of sea otters near active operations.
Sea otters that encounter the specified activity may exert more
energy than they would otherwise, due to temporary cessation of
feeding, increased vigilance, and retreating from the project area. We
expect that affected sea otters will tolerate this exertion without
measurable effects on health or reproduction. Most of the anticipated
takes will be due to short-term Level B harassment in the form of TTS,
startle reactions, or temporary displacement. While mitigation measures
incorporated into the applicant's request will reduce occurrences of
Level A harassment to the extent practicable, a small number of takes
by Level A harassment would be authorized for impact and DTH pile-
driving activities, which have Level A harassment zone radii ranging in
size from 5.2 to 67.1 m (17 to 220 ft).
With the adoption of the mitigation measures incorporated in the
applicant's request and required by this proposed IHA, anticipated take
was reduced. Those mitigation measures are further described below.
Small Numbers
To assess whether the authorized incidental taking would be limited
to ``small numbers'' of marine mammals, the Service uses a proportional
approach that considers whether the estimated number of marine mammals
to be subjected to incidental take is small relative to the population
size of the species or stock. Here, predicted levels of take were
determined based on the estimated density of sea otters in the project
area and ensonification zones developed using empirical evidence from
similar geographic areas.
We estimate that the City's specified activities in the specified
geographic region will result in no more than 790 takes of 77 sea
otters by Level B harassment and 30 takes of 5 sea otters by Level A
harassment during the 1-year period of this proposed IHA (see Sum of
Harassment from All Sources). Take of 82 animals is 0.4 percent of the
best available estimate of the current Southcentral Alaska stock size
of 21,617 animals (Esslinger et al. 2021) ((82 / 21,617) x 100 [ap]
0.4) and represents a ``small number'' of sea otters of that stock.
Negligible Impact
We propose a finding that any incidental take by harassment
resulting from the specified activities cannot be reasonably expected
to, and is not reasonably likely to, adversely affect the sea otter
through effects on annual rates of recruitment or survival and will,
therefore, have no more than a negligible impact on the Southcentral
Alaska stock of northern sea otters. In making this finding, we
considered the best available scientific information, including the
biological and behavioral characteristics of the species, the most
recent information on species distribution and abundance within the
area of the specified activities, the current and expected future
status of the stock (including existing and foreseeable human and
natural stressors), the potential sources of disturbance caused by the
project, and the potential responses of marine mammals to this
disturbance. In addition, we reviewed applicant-provided materials,
information in our files and datasets, published reference materials,
and species experts.
Sea otters are likely to respond to planned activities with
temporary behavioral modification or temporary displacement. These
reactions are not anticipated to have consequences for the long-term
health, reproduction, or survival of affected animals. Most animals
will respond to disturbance by moving away from the source, which may
cause temporary interruption of foraging, resting, or other natural
behaviors. Affected animals are expected to resume normal behaviors
soon after exposure, with no lasting consequences. Each sea otter is
estimated to be exposed to construction noise for between 3 and 170
days per year, resulting in repeated exposures.
[[Page 76238]]
However, injuries (i.e., Level A harassment or PTS) due to chronic
sound exposure are estimated to occur over a longer time scale
(Southall et al. 2019). The area that will experience noise greater
than Level B thresholds due to pile driving is small (less than 0.0141
km\2\), and an animal that may be disturbed could escape the noise by
moving to nearby quiet areas. Further, sea otters spend over half of
their time above the surface during the summer months (Esslinger et al.
2014), and likely no more than 70 percent of their time foraging during
winter months (Gelatt et al. 2002); thus, their ears will not be
exposed to continuous noise, and the amount of time it may take for
permanent injury is considerably longer than that of mammals primarily
under water. Some animals may exhibit some of the stronger responses
typical of Level B harassment, such as fleeing, interruption of
feeding, or flushing from a haulout. These responses could have
temporary biological impacts for affected individuals, but are not
anticipated to result in measurable changes in survival or
reproduction.
The total number of animals affected and severity of impact are not
sufficient to change the current population dynamics at the stock
scale. Although the specified activities may result in approximately
820 incidental takes of 82 sea otters from the Southcentral Alaska
stock, we do not expect this level of harassment to affect annual rates
of recruitment or survival or result in adverse effects on the stock.
Our proposed finding of negligible impact applies to incidental
take associated with the specified activities as mitigated by the
avoidance and minimization measures identified in the applicant's
mitigation and monitoring plan. These mitigation measures are designed
to minimize interactions with and impacts to sea otters. These measures
and the monitoring and reporting procedures are required for the
validity of our finding and are a necessary component of the proposed
IHA. For these reasons, we propose a finding that the specified project
will have a negligible impact on the Southcentral Alaska stock of
northern sea otters.
Least Practicable Adverse Impacts
We find that the mitigation measures required by this proposed IHA
will affect the least practicable adverse impacts on the stocks from
any incidental take likely to occur in association with the specified
activities. In making this finding, we considered the biological
characteristics of sea otters, the nature of the specified activities,
the potential effects of the activities on sea otters, the documented
impacts of similar activities on sea otters, and alternative mitigation
measures.
In evaluating what mitigation measures are appropriate to ensure
the least practicable adverse impact on species or stocks and their
habitat, as well as subsistence uses, we considered the manner and
degree to which the successful implementation of the measures are
expected to achieve this goal. We considered the nature of the
potential adverse impact being mitigated (likelihood, scope, range),
the likelihood that the measures will be effective if implemented, and
the likelihood of effective implementation. We also considered the
practicability of the measures for applicant implementation (e.g.,
cost, impact on operations). We assessed whether any additional
practicable requirements could be implemented to further reduce
effects, but did not identify any.
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, the City of Cordova will implement
mitigation measures, including the following:
Using a project design that incorporates the smallest
diameter piles and footprint practicable while minimizing the overall
number of piles and area;
Using a project design that does not include dredging or
excavating below the high tide line;
Using a project design that does not include blasting;
Using pile driving equipment with muffler systems to
reduce in-air noise generation;
Using a vibratory hammer equipped with a suppressor to
reduce rattling;
Using dampeners to eliminate steel-on-steel in-air noise;
Employing a sediment curtain during all DTH pile driving
to contain drill spoils and to minimize turbidity;
Development of a marine mammal monitoring and mitigation
plan;
Establishment of shutdown and monitoring zones;
Visual mitigation monitoring by designated protected
species observers (PSO);
Site clearance before startup;
Soft-start procedures; and
Shutdown procedures.
The Service has not identified any additional (i.e., not already
incorporated into the applicant's request) mitigation or monitoring
measures that are practicable and would further reduce potential
impacts to sea otters and their habitat.
Impact on Subsistence Use
The project will not preclude access to harvest areas or interfere
with the availability of sea otters for harvest. Additionally, the
construction activities take place within the Cordova Harbor, where
firearm use is prohibited. We therefore propose a finding that the
applicant's anticipated harassment will not have an unmitigable adverse
impact on the availability of any stock of northern sea otters for
taking for subsistence uses. In making this finding, we considered the
timing and location of the planned activities and the timing and
location of subsistence harvest activities in the project area.
Monitoring and Reporting
The purposes of the monitoring requirements are to document and
provide data for assessing the effects of specified activities on sea
otters; to ensure that take is consistent with that anticipated in the
small numbers, negligible impact, and subsistence use analyses; and to
detect any unanticipated effects on the species. Monitoring plans
include steps to document when and how sea otters are encountered and
their numbers and behaviors during these encounters. This information
allows the Service to measure encounter rates and trends and to
estimate numbers of animals potentially affected. To the extent
possible, monitors will record group size, age, sex, reaction, duration
of interaction, and closest approach to the project activity.
As proposed, monitoring activities will be summarized and reported
in formal reports. The applicant must submit monthly reports for all
months during which noise-generating work takes place as well as a
final monitoring report that must submitted no later than 90 days after
the expiration of the IHA. We will require an approved plan for
monitoring and reporting the effects of pile driving and marine
construction activities on sea otters prior to issuance of an IHA. We
will require approval of the monitoring results for continued operation
under the IHA.
We find that these proposed monitoring and reporting requirements
to evaluate the potential impacts of planned activities will ensure
that the effects of the activities remain consistent with the rest of
the findings.
Required Determinations
National Environmental Policy Act (NEPA)
We have prepared a draft environmental assessment in accordance
with the NEPA (42 U.S.C.
[[Page 76239]]
4321 et seq.). We have preliminarily concluded that authorizing the
nonlethal, incidental, unintentional take by Level B harassment of up
to 790 takes of 77 sea otters and by Level A harassment of up to 30
takes of 5 sea otters from the Southcentral Alaska stock in the
specified geographic region during the specified activities during the
regulatory period would not significantly affect the quality of the
human environment and, thus, preparation of an environmental impact
statement for this proposed IHA is not required by section 102(2) of
NEPA or its implementing regulations. We are accepting comments on the
draft environmental assessment as specified above in DATES and
ADDRESSES.
Government-to-Government Consultation
It is our responsibility to communicate and work directly on a
Government-to-Government basis with federally recognized Alaska Native
Tribes in developing programs for healthy ecosystems. We seek their
full and meaningful participation in evaluating and addressing
conservation concerns for protected species. It is our goal to remain
sensitive to Alaska Native culture, and to make information available
to Alaska Tribal organizations and communities. Our efforts are guided
by the following policies and directives:
(1) The Native American Policy of the Service (January 20, 2016);
(2) The Alaska Native Relations Policy (currently in draft form);
(3) Executive Order 13175 (January 9, 2000);
(4) Department of the Interior Secretary's Orders 3206 (June 5,
1997), 3225 (January 19, 2001), 3317 (December 1, 2011), and 3342
(October 21, 2016);
(5) The Alaska Government-to-Government Policy (a departmental
memorandum issued January 18, 2001); and
(6) The Department of the Interior's policies on consultation with
Alaska Native Tribes and organizations.
We have evaluated possible effects of the specified activities on
federally recognized Alaska Native Tribes and organizations. The
Service has determined that, due to this project's locations and
activities, the Tribal organizations and communities near Cordova,
Alaska, as well as relevant Alaska Native Claims Settlement Act
corporations, will not be impacted by this project. Regardless, we will
be reaching out to them to inform them of the availability of this
proposed IHA and offer them the opportunity to consult.
We invite continued discussion, either about the project and its
impacts or about our coordination and information exchange throughout
the IHA process.
Proposed Authorization
We propose to authorize the nonlethal incidental take by Level A
and Level B harassment of 820 takes of 82 sea otters from the
Southcentral Alaska stock. Authorized take may be caused by pile
driving and marine construction activities conducted by the City of
Cordova in Cordova, Alaska, over the course of a year from the date of
issuance of the IHA. We do not anticipate or authorize any lethal take
to sea otters resulting from these activities.
A. General Conditions for the Incidental Harassment Authorization (IHA)
(1) Activities must be conducted in the manner described in the
request from the City of Cordova for an IHA and in accordance with all
applicable conditions and mitigation measures. The taking of sea otters
whenever the required conditions, mitigation, monitoring, and reporting
measures are not fully implemented as required by the IHA is
prohibited. Failure to follow the measures specified both in the
request and within this proposed authorization may result in the
modification, suspension, or revocation of the IHA.
(2) If project activities cause unauthorized take (i.e., greater
than 820 takes of 82 of the Southcentral Alaska stock of northern sea
otters, a form of take other than Level A or Level B harassment, or
take of one or more sea otters through methods not described in the
IHA), the City of Cordova must take the following actions:
(i) cease its activities immediately (or reduce activities to the
minimum level necessary to maintain safety);
(ii) report the details of the incident to the Service within 48
hours; and
(iii) suspend further activities until the Service has reviewed the
circumstances and determined whether additional mitigation measures are
necessary to avoid further unauthorized taking.
(3) All operations managers, vehicle operators, and machine
operators must receive a copy of this IHA and maintain access to it for
reference at all times during project work. These personnel must
understand, be fully aware of, and be capable of implementing the
conditions of the IHA at all times during project work.
(4) This IHA will apply to activities associated with the specified
project as described in this document and in the City of Cordova's
request. Changes to the specified project without prior authorization
may invalidate the IHA.
(5) The City of Cordova's request is approved and fully
incorporated into this IHA unless exceptions are specifically noted
herein. The request includes:
(i) The City of Cordova's original request for an IHA, dated
February 28, 2023;
(ii) Revised requests, dated April 27, May 18, and June 8, 2023;
(iii) Marine Mammal Mitigation and Monitoring Plan; and
(iv) Google Earth package;
(6) Operators will allow Service personnel or the Service's
designated representative to visit project worksites to monitor for
impacts to sea otters and subsistence uses of sea otters at any time
throughout project activities, so long as it is safe to do so.
``Operators'' are all personnel operating under the City of Cordova's
authority, including all contractors and subcontractors.
B. Avoidance and Minimization
(7) Construction activities must be conducted using equipment that
generates the lowest practicable levels of underwater sound within the
range of frequencies audible to sea otters.
(8) During all pile-installation activities, regardless of
predicted sound levels, a physical interaction shutdown zone of 10 m
(33 ft) must be enforced. If a sea otter enters the shutdown zone, in-
water activities must be delayed until either the animal has been
visually observed outside the shutdown zone, or 15 minutes have elapsed
since the last observation time without redetection of the animal.
(9) If the impact driver has been idled for more than 30 minutes,
an initial set of three strikes from the impact driver must be
delivered at reduced energy, followed by a 1-minute waiting period,
before full powered proofing strikes.
(10) In-water activity must be conducted in daylight. If
environmental conditions prevent visual detection of sea otters within
the shutdown zone, in-water activities must be stopped until visibility
is regained.
(11) All in-water work along the shoreline must be conducted during
low tide when the site is dewatered to the maximum extent practicable.
C. Mitigation Measures for Vessel Operations
Vessel operators must take every precaution to avoid harassment of
sea otters when a vessel is operating near these animals. The applicant
must carry out the following measures:
(12) Vessels must remain at least 500 m (0.3 mi) from rafts of sea
otters, unless
[[Page 76240]]
safety is a factor. Vessels must reduce speed and maintain a distance
of 100 m (328 ft) from all sea otters, unless safety is a factor.
(13) Vessels must not be operated in such a way as to separate
members of a group of sea otters from other members of the group, and
must avoid alongshore travel in shallow water (<20 m (66 ft)) whenever
practicable.
(14) When weather conditions require, such as when visibility
drops, vessels must adjust speed accordingly to avoid the likelihood of
injury to sea otters.
(15) Vessel operators must be provided written guidance for
avoiding collisions and minimizing disturbances to sea otters. Guidance
will include measures identified in paragraphs (C)(12) through (15) of
this section.
D. Monitoring
(16) Operators shall work with protected species observers (PSO) to
apply mitigation measures and shall recognize the authority of PSOs up
to and including stopping work, except where doing so poses a
significant safety risk to personnel.
(17) Duties of the PSOs include watching for and identifying sea
otters, recording observation details, documenting presence in any
applicable monitoring zone, identifying and documenting potential
harassment, and working with operators to implement all appropriate
mitigation measures.
(18) A sufficient number of PSOs will be available to meet the
following criteria: 100 percent monitoring of exclusion zones during
all daytime periods of underwater noise-generating work; a maximum of 4
consecutive hours on watch per PSO; a maximum of approximately 12 hours
on watch per day per PSO.
(19) All PSOs will complete a training course designed to
familiarize individuals with monitoring and data collection procedures.
A field crew leader with prior experience as a sea otter observer will
supervise the PSO team. Initially, new or inexperienced PSOs will be
paired with experienced PSOs so that the quality of marine mammal
observations and data recording is kept consistent. Resumes for
candidate PSOs will be made available for the Service to review.
(20) Observers will be provided with reticule binoculars (7x50 or
better), big-eye binoculars or spotting scopes (30x), inclinometers,
and range finders. Field guides, instructional handbooks, maps, and a
contact list will also be made available.
(21) Observers will collect data using the following procedures:
(i) All data will be recorded onto a field form or database.
(ii) Global positioning system data, sea state, wind force, and
weather will be collected at the beginning and end of a monitoring
period, every hour in between, at the change of an observer, and upon
sightings of sea otters.
(iii) Observation records of sea otters will include date; time;
the observer's locations, heading, and speed (if moving); weather;
visibility; number of animals; group size and composition (adults/
juveniles); and the location of the animals (or distance and direction
from the observer).
(iv) Observation records will also include initial behaviors of the
sea otters, descriptions of project activities and underwater sound
levels being generated, the position of sea otters relative to
applicable monitoring and mitigation zones, any mitigation measures
applied, and any apparent reactions to the project activities before
and after mitigation.
(v) For all sea otters in or near a mitigation zone, observers will
record the distance from the sound source to the sea otter upon initial
observation, the duration of the encounter, and the distance at last
observation in order to monitor cumulative sound exposures.
(vi) Observers will note any instances of animals lingering close
to or traveling with vessels for prolonged periods of time.
(22) Monitoring of the shutdown zone must continue for 30 minutes
following completion of pile installation.
E. Measures To Reduce Impacts to Subsistence Users
(23) Prior to conducting the work, the City of Cordova will take
the following steps to reduce potential effects on subsistence harvest
of sea otters:
(i) Avoid work in areas of known sea otter subsistence harvest;
(ii) If any concerns remain, develop a plan of cooperation in
consultation with the Service and subsistence stakeholders to address
these concerns.
F. Reporting Requirements
(24) The City of Cordova must notify the Service at least 48 hours
prior to commencement of activities.
(25) Monthly reports will be submitted to the Service's Marine
Mammal Management office (MMM) for all months during which noise-
generating work takes place. The monthly report will contain and
summarize the following information: dates, times, weather, and sea
conditions (including the Beaufort Scale sea state and wind force
conditions) when sea otters were sighted; the number, location,
distance from the sound source, and behavior of the sea otters; the
associated project activities; and a description of the implementation
and effectiveness of mitigation measures with a discussion of any
specific behaviors the sea otters exhibited in response to mitigation.
(26) A final report will be submitted to the Service's MMM within
90 days after completion of work or expiration of the IHA. The report
will include:
(i) A summary of monitoring efforts (hours of monitoring,
activities monitored, number of PSOs, and, if requested by the Service,
the daily monitoring logs).
(ii) A description of all project activities, along with any
additional work yet to be done. Factors influencing visibility and
detectability of marine mammals (e.g., sea state, number of observers,
and fog and glare) will be discussed.
(iii) A description of the factors affecting the presence and
distribution of sea otters (e.g., weather, sea state, and project
activities). An estimate will be included of the number of sea otters
exposed to noise at received levels greater than or equal to 160 dB
(based on visual observation).
(iv) A description of changes in sea otter behavior resulting from
project activities and any specific behaviors of interest.
(v) A discussion of the mitigation measures implemented during
project activities and their observed effectiveness for minimizing
impacts to sea otters. Sea otter observation records will be provided
to the Service in the form of electronic database or spreadsheet files.
(27) Injured, dead, or distressed sea otters that are not
associated with project activities (e.g., animals known to be from
outside the project area, previously wounded animals, or carcasses with
moderate to advanced decomposition or scavenger damage) must be
reported to the Service within 24 hours of the discovery to either the
Service's MMM (1-800-362-5148, business hours), the Alaska SeaLife
Center in Seward (1-888-774-7325, 24 hours a day), or both.
Photographs, video, location information, or any other available
documentation must be provided to the Service.
(28) All reports shall be submitted by email to
[email protected].
(29) The City of Cordova must notify the Service upon project
completion or end of the work season.
Request for Public Comments
If you wish to comment on this proposed authorization, the
associated
[[Page 76241]]
draft environmental assessment, or both documents, you may submit your
comments by either of the methods described in ADDRESSES. Please
identify whether you are commenting on the proposed authorization,
draft environmental assessment, or both, make your comments as specific
as possible, confine them to issues pertinent to the proposed
authorization, and explain the reason for any changes you recommend.
Where possible, your comments should reference the specific section or
paragraph that you are addressing. The Service will consider all
comments that are received before the close of the comment period (see
DATES). The Service does not anticipate extending the public comment
period beyond the 30 days required under section 101(a)(5)(D)(iii) of
the MMPA.
Comments, including names and street addresses of respondents, will
become part of the administrative record for this proposal. Before
including your address, telephone number, email address, or other
personal identifying information in your comment, be advised that your
entire comment, including your personal identifying information, may be
made publicly available at any time. While you can ask us in your
comments to withhold from public review your personal identifying
information, we cannot guarantee that we will be able to do so.
Peter Fasbender,
Assistant Regional Director Fisheries and Ecological Services, Alaska
Region.
[FR Doc. 2023-24428 Filed 11-3-23; 8:45 am]
BILLING CODE 4333-15-P