[Federal Register Volume 84, Number 132 (Wednesday, July 10, 2019)]
[Notices]
[Pages 32932-32945]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-14667]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
[Docket No. FWS-R7-ES-2019-0053; FXES111607MRG01-190-FF07CAMM00]
Marine Mammals; Incidental Take During Specified Activities;
Proposed Incidental Harassment Authorizations for Northern Sea Otters
in Southeast Alaska
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of receipt of applications and proposed incidental
harassment authorizations; availability of draft environmental
assessments; request for comments.
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SUMMARY: We, the U.S. Fish and Wildlife Service, have received two
requests, one from the City and Borough of Sitka (CBS) and one from
Duck Point Development II, LLC (DPD), for authorization to take small
numbers of the southeast Alaska stock of northern sea otters incidental
to pile driving in Sitka Sound and Port Frederick, Alaska, between
April 1, 2019, and September 30, 2019. However, due to the time needed
to process the request, we evaluated the estimated take of northern sea
otters during project activities between July 22, 2019, and December
31, 2019. We estimate there may be up to 12 nonlethal, incidental takes
by harassment of 4 northern sea otters for the CBS project, and up to
1,380 nonlethal, incidental takes by harassment of 220 northern sea
otters for the DPD project. In accordance with provisions of the Marine
Mammal Protection Act of 1972, we request comments on our proposed
authorizations, which, if finalized, will be for take by Level B
harassment only. We anticipate no take by injury or death and include
none in these proposed authorizations.
DATES: Comments on the proposed incidental harassment authorizations
and draft environmental assessments must be received by August 9, 2019.
ADDRESSES: Document availability: You may view these proposed
authorizations, the application packages, supporting information, draft
environmental assessments, and the
[[Page 32933]]
lists of references cited herein at http://www.regulations.gov under
Docket No. FWS-R7-ES-2019-0053, or these documents may be requested as
described under FOR FURTHER INFORMATION CONTACT. You may submit
comments on these proposed authorizations by one of the following
methods:
U.S. mail or hand-delivery: Public Comments Processing,
Attn: Docket No. FWS-R7-ES-2019-0053, Division of Policy, Performance,
and Management Programs, U.S. Fish and Wildlife Service, 5275 Leesburg
Pike, MS: BPHC, Falls Church, VA 22041-3803.
Electronic submission: Federal eRulemaking Portal at:
http://www.regulations.gov. Follow the instructions for submitting
comments to Docket No. FWS-R7-ES-2019-0053.
We will post all comments at http://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: Mr. Christopher Putnam, U.S. Fish and
Wildlife Service, 1011 East Tudor Road, MS 341, Anchorage, Alaska,
99503, by email at fw7_ak_marine_mammalst@fws.gov, or by telephone at
1-800-362-5148. Persons who use a telecommunications device for the
deaf (TDD) may call the Federal Relay Service (FRS) at 1-800-877-8339.
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 of
a species or population stock by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
region during a period of not more than 1 year. Incidental take by
harassment may be authorized only if statutory and regulatory
procedures are followed and the U.S. Fish and Wildlife Service
(hereafter, ``the Service'' or ``we'') makes the following findings:
(i) Take is of a small number of animals, (ii) take will have a
negligible impact on the species or stock, and (iii) take will not have
an unmitigable adverse impact on the availability of the species or
stock for subsistence uses by coastal-dwelling Alaska Natives.
The term ``take,'' as defined by the MMPA, means to harass, hunt,
capture, or kill, or to attempt to harass, hunt, capture, or kill any
marine mammal (16 U.S.C. 1362(13)). Harassment, as defined by the MMPA,
means any act of pursuit, torment, or annoyance that (i) has the
potential to injure a marine mammal or marine mammal stock in the wild
(the MMPA calls this ``Level A harassment''), or (ii) has the potential
to disturb a marine mammal or marine mammal stock in the wild by
causing disruption of behavioral patterns, including, but not limited
to, migration, breathing, nursing, breeding, feeding, or sheltering
(the MMPA calls this ``Level B harassment'').
The terms ``negligible impact,'' ``small numbers,'' and
``unmitigable adverse impact'' are defined in the Code of Federal
Regulations at 50 CFR 18.27, the Service's regulations governing take
of small numbers of marine mammals incidental to specified activities.
``Negligible impact'' is defined as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival. Although ``small
numbers'' is defined in 50 CFR 18.27, we do not rely on that definition
as it conflates the terms ``small numbers'' and ``negligible impact,''
which we recognize as two separate and distinct requirements (see
Natural Res. Def. Council, Inc. v. Evans, 232 F. Supp. 2d 1003, 1025
(N.D. Cal. 2003)). In our determination, we evaluate ``small numbers''
by analyzing the number of marine mammals likely to be taken in
relation to the size of the overall stock. ``Unmitigable adverse
impact'' is defined as 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.
If the requisite findings are made, we issue an incidental
harassment authorization (IHA), which sets forth the following: (i)
Permissible methods of taking; (ii) other means of effecting the least
practicable impact on marine mammals and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of marine mammals for taking for
subsistence uses by coastal-dwelling Alaska Natives; and (iii)
requirements for monitoring and reporting take.
Summary of Requests
City and Borough of Sitka--O'Connell Bridge Lightering Float
On November 12, 2018, the City and Borough of Sitka, Alaska,
(hereafter ``CBS'') submitted a request to the Service's Marine Mammals
Management Office (MMM) for authorization to take by harassment a small
number of northern sea otters (Enhydra lutris kenyoni, hereafter also
``sea otters'' or ``otters''). Following requests for additional
information, CBS submitted an amended application on March 21, 2019,
and additional information was received on March 25, 2019. The
applicant expects that take by incidental harassment may occur during
its planned pile-driving activities at the O'Connell Bridge dock
facility located in Sitka, Alaska.
Duck Point Development II, LLC--Hoonah Berth II Project
On January 30, 2019, Duck Point Development II, LLC, (hereafter
``DPD'') submitted a request to the Service's MMM for authorization to
take by harassment a small number of sea otters. Following requests for
additional information, DPD submitted an amended application on March
21, 2019. The applicant expects that take by incidental harassment may
occur during their planned pile-driving activities at Cannery Point
located near Hoonah, Alaska.
Description of Specified Activities and Geographic Area
City and Borough of Sitka--O'Connell Bridge Lightering Float
The specified activity (the ``project'') consists of CBS's proposed
repairs to the O'Connell Bridge Lightering Float, specifically the
removal and replacement of six 16-inch-diameter steel pipe piles. CBS
will conduct work on 3 days between July 22, 2019, and December 31,
2019.
Removal of the extant piles will be accomplished by either dry pull
or vibratory extraction. Sockets to accommodate the replacement piles
will be drilled so that the piles may be installed to a greater depth
than that of the existing piles, allowing for the accommodation of
larger vessels. The replacement piles will be installed using both
vibratory and impact methods. Transfer of personnel and equipment
between shore and the work platform will be done using skiffs
approximately 7.6-10.7 meters (m) or 25-30 feet (ft) in length with a
35-50 horsepower (hp)
[[Page 32934]]
outboard engine. Further information and technical specifications can
be found in CBS's IHA application available at: http://www.regulations.gov, Docket No. FWS-R7-ES-2019-0053.
Duck Point Development II, LLC--Hoonah Berth II Project
The project at Hoonah consists of two components: (1) The
installation of a lightering float at the existing dock facility on the
southwest side of Cannery Point; and (2) the installation of a cruise
ship berth on the northeast side of Cannery Point. This will involve
the installation and subsequent removal of up to 62 temporary 30-inch
piles and installation of 45 permanent piles ranging from 24 to 42
inches in diameter. Temporary piles will be installed and removed by
vibratory extraction; permanent piles will be installed using both
vibratory and impact methods. Additionally, there will be socket and
anchor drilling to secure piles at depth. Transfer of personnel and
equipment between shore and the work platform will be done using skiffs
approximately 7.6-10.7 m (25-30 ft) in length with a 35-50 hp outboard
engine, and a similar vessel will be used for visual monitoring of
marine mammals in the waters of Port Frederick and parts of Icy Strait.
Work will take place over a 75-day period between July 22, 2019, and
December 31, 2019. Further information and technical specifications can
be found in DPD's IHA application at: http://www.regulations.gov,
Docket No. FWS-R7-ES-2019-0053.
Description of Marine Mammals in the Specified Area
The northern sea otter is currently the only marine mammal under
the Service's jurisdiction that normally occupies Sitka Sound and Port
Frederick, Alaska. There are three stocks of northern sea otters in
Alaska. These are the southeast, southcentral, and southwest stocks.
Sea otters that occur in Sitka Sound and Port Frederick/Icy Strait
belong to the southeast Alaska stock. The Service's most recent stock
assessment report is available at https://www.fws.gov/alaska/fisheries/mmm/stock/Revised_April_2014_Southeast_Alaska_Sea_Otter_SAR.pdf.
Sea otters may occur anywhere within the specified project area
other than upland areas. Abundance and densities of the southeast
Alaska stock of sea otters were estimated from aerial surveys conducted
by the Service in cooperation with the U.S. Geological Survey (USGS)
between 1995 and 2012 (Tinker et al., in press). Total abundance in the
northern region of Southeast Alaska was estimated to be 11,635 sea
otters, with over half (7,955) of these animals occurring in Glacier
Bay (Tinker et al., in press). Densities of sea otters in the project
areas were estimated at 0.842 otters per square km (km\2\) in Sitka
Sound and 0.368 otters per km\2\ in Port Frederick and Icy Strait
(Tinker et al., in press).
Sea otters generally occur in shallow water near the shoreline.
They are most commonly observed within the 40-m (131-ft depth contour
(USFWS, 2014), although they can be found in areas with deeper water.
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 remain closer to
shore during storms, but they may be found farther from shore when seas
are calm (Lensink 1962; Kenyon 1969).
Sea otters are non-migratory and generally do not disperse over
long distances (Garshelis and Garshelis 1984). They usually remain
within a few kilometers of their established feeding grounds (Kenyon
1981). Breeding males remain for all or part of the year in a breeding
territory covering up to 1 km (0.62 mi) of coastline. Adult females
have 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). Although sea otters generally remain local to an area,
they are capable of long-distance travel. Otters in Alaska have shown
daily movement distances greater than 3 km (1.9 mi) at speeds up to 5.5
km/hour (3.4 mi/hour) (Garshelis and Garshelis 1984).
Potential Effects of the Activities
Exposure of Sea Otters to Noise
The applicants have requested authorizations for Level B incidental
harassment of the southeast Alaska stock of northern sea otters. Otters
in the project area will be exposed to the visual and auditory
stimulation associated with the presence and operation of pile-driving
equipment and support vessels. Vessel traffic and human presence on
docks are common in Sitka Sound and Port Frederick/Icy Strait; however,
pile-driving operations will create sounds that are unfamiliar to
otters in these areas. If sea otters are disturbed, it will likely be
due to the underwater noise associated with pile-driving operations, or
possibly, the noise in tandem with the sight of equipment and vessels.
Pile driving and vessel operations may cause disruptions to
biologically significant sea otter behavioral patterns, thereby
resulting in incidental take by Level B harassment.
Noise From Pile Driving
During the course of pile driving, a portion of the kinetic energy
from the hammer is lost to the water column in the form of sound.
Levels of underwater sounds produced during pile driving are dependent
upon the size and composition of the pile, the substrate into which the
pile is driven, bathymetry, physical and chemical characteristics of
the surrounding waters, and pile installation method (Illingworth and
Rodkin 2007, 2014; Denes et al. 2016).
Both impact and vibratory pile installation produce underwater
sounds of frequencies predominantly lower than 2.5 kilohertz (kHz),
with the highest intensity of pressure spectral density at or below 1
kHz (Denes et al. 2016; Dahl et al. 2015; Illingworth and Rodkin 2007).
Source levels of underwater sounds produced by impact pile driving tend
to be higher than for vibratory pile driving; however, both methods of
installation can generate underwater sound levels capable of causing
behavioral disturbance or hearing threshold shift in marine mammals. A
summary of the properties of sounds produced by the proposed activities
can be found in table 1.
Whether a specific noise source will affect an otter depends on
several factors, including the distance between the animal and the
sound source, the sound intensity, background noise levels, the noise
frequency, duration, and whether the noise is pulsed or continuous. The
actual noise level perceived by individual otters will depend on
distance to the pile-driving site, whether the animal is above or below
water, atmospheric and environmental conditions, and the operational
parameters of the piles and pile-driving equipment being used.
[[Page 32935]]
Table 1--Summary of Acoustic Source Levels for Proposed Activities
----------------------------------------------------------------------------------------------------------------
Sound pressure
Applicant Activity levels (dB re 1 Frequency References
[micro]Pa)
----------------------------------------------------------------------------------------------------------------
CBS............... Impact pile driving 181.3 dBPK @10 m Up to 2.5 kHz........... Austin et al. 2016;
(168.2 dBSEL @10 Denes et al. 2016.
m).
CBS............... Vibratory pile 161 @10 m.......... Up to 2.5 kHz........... Austin et al. 2016;
installation/ Denes et al. 2016.
removal.
CBS............... Socket drilling.... 189.8 @1 m......... Up to 10 kHz............ Denes et al. 2016.
CBS............... General vessel 145-175 dB rms @1 m 10-1,500 Hz............. Richardson et al. 1995;
operations. Kipple and Gabriele
2004; Ireland and
Bisson 2016.
CBS............... Barge operations... 180 dB rms @1 m.... 10-1,500 Hz............. Richardson et al. 1995;
Kipple and Gabriele
2004; Ireland and
Bisson 2016.
DPD............... Impact pile driving 198.6 dBPK @10 m Up to 2.5 kHz........... Austin et al. 2016;
(186.7 dBSEL @10 Denes et al. 2016.
m).
DPD............... Vibratory pile 161.9 to 168.2 @10 Up to 2.5 kHz........... Austin et al. 2016;
installation/ m. Denes et al. 2016.
removal.
DPD............... Socket and anchor 189.8 @1 m......... Up to 10 kHz............ Denes et al. 2016.
drilling.
DPD............... General vessel 145-175 dB rms @1 m 10-1,500 Hz............. Richardson et al. 1995;
operations. Kipple and Gabriele
2004; Ireland and
Bisson 2016.
DPD............... Barge operations... 180 dB rms @1 m.... 10-1,500 Hz............. Richardson et al. 1995;
Kipple and Gabriele
2004; Ireland and
Bisson 2016.
----------------------------------------------------------------------------------------------------------------
CBS = City and Borough of Sitka, DPD = Duck Point Development II, LLC for Hoonah Berth II, dBPK = Decibels peak,
dBSEL = Decibels sound exposure level, dBRMS = Decibels root mean squared.
Noise From Vessels
Characteristics of sounds produced by vessels are a product of
several variables pertaining to the specifications of the vessel,
including the number and type of engines, propeller shape and size, and
the mechanical condition of these components. Operational status of the
vessel, such as pushing or towing heavy loads, or using bow thrusters,
can significantly affect the levels of sounds emitted by the same
vessel at different times (Richardson et al. 1995; Ireland and Bisson
2016).
The proposed vessels are skiffs approximately 7.6-10.7 m (25-30 ft)
in length with 35-50 hp outboard engines. Recordings of sounds produced
by similar vessels in Glacier Bay National Park were loudest at
frequencies between roughly 100 Hertz (Hz) and 5 kHz, with source
levels ranging from 160-182 Decibels referenced at 1 micro Pascal at 1
meter (dB re 1 [micro]Pa at 1 m) (Kipple and Gabriele 2004). Acoustic
properties of sounds expected from vessel operations are shown in table
1.
Sea Otter Hearing
Sound frequencies produced by vessels, pile driving, and removal
equipment will fall within the hearing range of northern sea otters and
will be audible to animals during the proposed construction activities.
Controlled sound exposure trials on southern sea otters (E. l. nereis)
indicate that those otters can hear frequencies between 125 Hz and 38
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) sounds than terrestrial
mustelids but similar to that of sea lions. 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
2012a).
Exposure to high levels of sound may cause changes in behavior,
masking of communications, temporary or permanent changes in hearing
sensitivity, discomfort, and injury. Species-specific criteria for sea
otters have not been identified for preventing harmful sound exposures.
Thresholds have been developed for other marine mammals, above which
exposure is likely to cause behavioral disturbance and injuries
(Southall et al. 2007, 2019; Finneran and Jenkins 2012; NMFS 2018a).
Because sea otter hearing abilities and sensitivities have not been
fully evaluated, we relied on functionally similar hearing information
from other species to evaluate the potential effects of noise exposure.
California sea lions (Zalophus californianus) (an otariid pinniped)
have shown a frequency range of hearing most functionally similar to
that of southern sea otters (Ghoul and Reichmuth 2014) and provide the
closest proxy for which data are available. Sea otters and otariid
pinnipeds share a similar mammalian aural physiology (Echteler et al.
1994; Solntseva 2007). Both are adapted to amphibious hearing, and both
use sound in similar ways.
Exposure Thresholds
Noise exposure criteria have been established by the NMFS for
identifying underwater noise levels capable of causing Level A
harassment (injury) of marine mammals, including otariid pinnipeds
(NMFS 2018a). Sea otter-specific criteria have not been established;
however, because of the biological similarities between otariid
pinnipeds and sea otters, we assume that noise criteria developed by
NMFS for injury for otariid pinnipeds are a suitable proxy for sea
otters. Those criteria are based on estimated levels of sound exposure
capable of causing a permanent shift in sensitivity of hearing (e.g., a
permanent threshold shift (PTS) (NMFS 2018a)). Exposure to moderate
durations of very loud noise or long-term continuous exposure of
moderate noise levels may cause the hairs within the inner ear system
to die or disable the synapses between hair cells and their neurons,
resulting in PTS.
NMFS's (2018a) criteria for sound exposure incorporate two metrics
of exposure: The peak level of instantaneous exposure likely to cause
PTS, and the effects of cumulative exposure 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. The estimated PTS
[[Page 32936]]
thresholds for otariid pinnipeds are 232 dB peak and 203 dB sound
exposure level cumulative (SELcum) for impulsive noise, and 219 dB
SELcum for non-impulsive noise (NMFS 2018a). NMFS criteria for Level A
harassment represents the best available information for predicting
injury from exposure to underwater sound among otariid pinnipeds. We
assume these criteria also represent appropriate exposure limits for
Level A harassment of sea otters. A recent review of literature
regarding the effects of noise upon the hearing of marine mammals
placed sea otters into a functional hearing group called ``other
carnivores'', which also includes otariid pinnipeds (Southall et al.
2019), but no new hearing threshold criteria were identified in that
study.
NMFS (2018a) criteria do not identify thresholds for avoidance of
Level B harassment. For pinnipeds, NMFS has adopted a 160-dB threshold
Level B harassment from exposure to impulse noise and a 120-dB
threshold for continuous noise (NMFS 1998; HESS 1999; NMFS undated).
These thresholds were developed from observations of mysticetes
responding to airgun operations (e.g., Malme et al. 1983a, 1983b;
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) reviewed the literature and derived TTS
thresholds for pinnipeds from impulsive sounds based on 212 dB peak and
171 dB SELcum. The updated review from Southall et al. (2019) gives
values of 232 dB peak and 203 dB SELCUM for the TTS
threshold for the ``other carnivore'' group. Kastak et al. (2005) found
exposures resulting in TTS in pinnipeds ranging from 152 to 174 dB
(183-206 dB SEL). Kastak et al. (2008) demonstrated persistent TTS, if
not PTS, after 60 seconds of 184 dB SEL. Kastelein et al. (2012) found
small but statistically significant TTSs at approximately 170 dB SEL
(136 dB, 60 min) and 178 dB SEL (148 dB, 15 min). Finneran (2015)
summarized these and other studies, which NMFS (2018a) has used to
develop a TTS threshold for otariid pinnipeds of 199 dB
SELCUM.
Southall et al. (2007) also assessed behavioral response studies
and found considerable variability among captive pinnipeds. They
determined that exposures between approximately 90-140 dB generally do
not induce strong behavioral responses in pinnipeds in water (Southall
et al. 2007). Avoidance and other behavioral effects were observed in
the range between 120-160 dB; however, only one of the observed
reactions reported in Southall et al. (2007) was sufficiently severe to
meet behavioral criteria for take by Level B harassment (see
Characterizing Take by Level B Harassment, below). In the Evidence from
Sea Otter Studies section below, we review the observed and studied
behavioral responses of wild sea otters to noise. Behavioral
observations indicate that a 120-dB threshold is likely to overestimate
the likelihood of Level B harassment, but these studies do not provide
definitive support for a particular threshold. Therefore, the work of
NMFS (2018a, undated), Southall et al. (2007, 2019), and others
described here represent the best available data and suggest that
either a 199-dB SELCUM threshold or a 160-dB threshold is
likely to be the best predictor of Level B harassment.
In conclusion, a 199-dB SELCUM exposure threshold is
likely to be more accurate than a 160-dB threshold when the behaviors
of individual otters can be closely monitored. Given the lack of TTS
data specific to otters, the 160-dB threshold provides a measure of
insurance against underestimation of the possible risks to otters, and
provides greater practicability for application of mitigation and
monitoring.
Exposure to impulsive sound levels greater than 160 dB can elicit
behavioral changes in marine mammals that might be detrimental to
health and long-term survival where it disrupts normal behavioral
routines. Thus, using information available for other marine mammals as
a surrogate, and taking into consideration the best available
information about sea otters, the Service has determined the received
sound level under water of 160 dB as a threshold for Level B take by
disturbance for sea otters for this proposed IHA (based on Ghoul and
Reichmuth 2012a,b; McShane et al. 1995; Riedman 1983; Richardson et al.
1995; and others). Exposure to unmitigated in-water noise levels
between 125 Hz and 38 kHz that are greater than 160 dB will be
considered by the Service as Level B take for both continuous and
impulsive sound sources; thresholds for potentially injurious Level A
take will be 232 dB peak or 203 dB SEL for impulsive sounds and 219 dB
SEL for continuous sounds (table 2).
Table 2--Summary of Northern Sea Otter Acoustic Thresholds for Underwater Sound in the Frequency Range 125 Hz-38
kHz
----------------------------------------------------------------------------------------------------------------
Injury (Level A) threshold Disturbance (Level B)
------------------------------------------------ threshold
Marine mammals ----------------------------
Impulsive \1\ Non-Impulsive \1\ All
----------------------------------------------------------------------------------------------------------------
Sea otters......................... 232 dB peak; 203 dB 219 dB SELCUM......... 160 dB rms.
SELCUM.
----------------------------------------------------------------------------------------------------------------
\1\ Based on NMFS acoustic criteria for otariid pinnipeds (NMFS 2018a).
Evidence From Sea Otter Studies
The available studies of northern and southern sea otter behavior
indicate that sea otters are somewhat more resistant to the effects of
sound than other marine mammals (Riedman 1983, 1984; Ghoul et al.
2012a, b; Reichmuth and Ghoul 2012). Southern sea otters off the
California coast showed only mild interest in boats passing within
hundreds of meters and appeared to have habituated to boat traffic
(Riedman 1983; Curland 1997). There are no available data regarding the
reactions of northern sea otters to pile driving. Southern sea otters
in an area with frequent railroad noise appeared to be relatively
undisturbed by pile-driving activities, many showing no response and
generally reacting more strongly to passing vessels than to the sounds
of pile-driving equipment (ESNERR 2011; ESA 2016). Additionally, many
of the otters who displayed a reaction behavior during pile driving did
so while their heads were above the surface of the water, suggesting
that airborne noise was as important as underwater noise in prompting
the animals' reactions. When sea otters have displayed behavioral
disturbance in response to acoustic stimuli, responses were short-
lived, and the otters quickly became habituated and resumed normal
activity (Davis et al. 1987, 1988; Ghoul et al. 2012b). Sea otters may
be less sensitive to noise as
[[Page 32937]]
they do not rely on sound to orient themselves, locate prey, or
communicate underwater.
Sea otters in Alaska have shown signs of disturbance (escape
behaviors) in response to the presence and approach of vessels.
Behaviors included diving or actively swimming away from a boat,
hauled-out sea otters entering the water, and groups of otters
dispersing and swimming in multiple different directions (Udevitz et
al. 1995). Sea otters in Alaska have also been shown to avoid areas
with heavy boat traffic but return to those same areas during seasons
with less traffic (Garshelis and Garshelis 1984).
Disturbance is possible from the applicants' activities. Individual
sea otters in Sitka Sound and Port Frederick/Icy Strait are likely to
show a range of responses to noise from the applicants' equipment and
vessels. Some may abandon the construction areas and return when the
disturbance has ceased. Based on the observed movement patterns of wild
otters (i.e., Lensink 1962; Kenyon 1969, 1981; Garshelis and Garshelis
1984; Riedman and Estes 1990), we expect that some individuals (e.g.,
independent juveniles) will respond to the applicants' proposed
activities by dispersing to nearby areas of suitable habitat while
others will not be displaced.
Some otters will likely show startle responses, change direction of
travel, or dive. Otters reacting to pile driving or vessels may divert
time and attention from biologically important behaviors, such as
feeding. Other effects may be undetectable in observations of behavior,
especially the physiological effects of chronic noise exposure. Some
otters in the area of activity may become habituated to noise caused by
the project due to the existing continual vessel traffic in the area
and will have little, if any, reaction to the presence of vessels or
human activity on the barge platforms.
Effects on Habitat
Habitat areas of significance for otters exist near the project
areas. Physical and biological features of coastal habitat essential to
the conservation of northern sea otters include the benthic
invertebrates (urchins, mussels, clams, etc.) eaten by otters and the
shallow rocky areas and kelp beds that provide cover from predators.
The CBS project involves the removal and replacement of piles at an
extant dock facility, and little to no habitat within Sitka Sound will
be altered. For the DPD project, the lightering float will be installed
between two busy commercial docks at Cannery Point. This area already
experiences frequent vessel traffic, and the addition of the lightering
float will not result in a substantial increase in vessel traffic to
the area. Therefore, it is unlikely that sea otter habitat would be
significantly modified by the addition of the lightering float.
The northeast side of Cannery Point--the proposed location for the
second cruise ship berth at Hoonah--is not developed and otters may be
displaced by the installation of the berth and a subsequent increase in
vessel traffic. Impacts upon benthic habitat of otters and their prey
are minimized by the use of a floating dock, which will not require
dredging or fill. The installation of the berth will increase vessel
traffic to the northeast side of Cannery Point where otters may become
habituated to traffic or may be displaced. However, passengers from
cruise ships are currently being transferred to shore a few at a time
on board small vessels. The presence of a facility at which passengers
can walk off a vessel to participate in shore excursions will bring
about a reduction in the number of small vessel trips between moored
cruise ships and the shore near Cannery Point.
Mitigation and Monitoring
If IHAs for the applicants' projects are issued, they must specify
means for effecting the least practicable impact on northern sea otters
and their habitat, paying particular attention to habitat areas of
significance, and on the availability of northern sea otters for taking
for subsistence uses by coastal-dwelling Alaska Natives.
In evaluating what mitigation measures are appropriate to ensure
the least practicable adverse impact on a species or stock and their
habitat, as well as subsistence uses, we considered the manner in
which, and the degree to which, the successful implementation of the
measures are expected to reduce impacts to sea otters, their habitat,
and their availability for subsistence uses. 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).
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, the applicants have proposed mitigation
measures including, but not limited to, the following:
Development of marine mammal monitoring and mitigation
plans;
Establishment of shutdown and monitoring zones during
noise-generating work;
Visual mitigation monitoring by designated Protected
Species Observers (PSOs);
Conducting all work during periods of good visibility;
Site clearance before start-up;
Soft-start procedures;
Shutdown procedures;
Use of pile caps to reduce noise during impact pile
driving; and
Vessel strike avoidance measures.
These measures are further specified under Proposed Authorizations,
part B. Avoidance and Minimization.
Estimated Incidental Take
Characterizing Take by Level B Harassment
An individual sea otter's reaction will depend on its prior
exposure to vessels and human presence at the project sites, some
intrinsic motivation or requirement to be in the particular area, its
physiological status, or other intrinsic factors. The location, timing,
frequency, intensity, and duration of the encounter are among the
external factors that will also influence the animal's response.
Relatively minor reactions such as increased vigilance or a short-
term change in direction of travel are not likely to disrupt
biologically important behavioral patterns and are not considered take
by harassment as defined by the MMPA. These types of responses typify
the most likely reactions of sea otters that will be exposed to the
applicants' activities. Extreme behavioral reactions capable of causing
injury are characterized as Level A harassment events, which are
unlikely to result from the proposed project and will not be
authorized. Intermediate reactions that disrupt biologically
significant behaviors of the affected animal meet the criteria for
Level B harassment under the MMPA. In 2014, the Service identified the
following sea otter behaviors as indicating possible Level B
harassment. The following list does not describe all possible
behaviors, and other situations may indicate 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 (spy hopping) while apparently agitated or while
swimming away;
In the case of a pup, repeatedly spy hopping while hiding
behind and holding onto its mother's head;
[[Page 32938]]
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 along the shoreline;
Ceasing mating behaviors;
Shifting/jostling/agitation in a raft so that the raft
disperses;
Sudden diving of an entire raft; and
Flushing animals off a haulout.
Estimating Exposure Rates
The Service anticipates that incidental harassment of sea otters
may occur during the proposed activities in Sitka Sound and Port
Frederick/Icy Strait. Underwater noise levels from pile driving and
related activities may cause short-term, nonlethal, but biologically
significant changes in behavior that the Service considers Level B
harassment. The number of animals affected will be determined by the
distribution of animals and their location in proximity to the project
work.
Sound exposure criteria provide the best available proxy for
estimation of exposure. The behavioral response of sea otters to
shoreline construction and vessel activities is related to the distance
between the activity and the animals. Underwater sound is generated in
tandem with other airborne visual, olfactory, or auditory signals from
the specified activities, and travels much farther. Therefore,
estimating exposure to underwater sound can be used to estimate
exposure to all proposed activities.
No separate exposure evaluation was done for activities that do not
generate underwater sound. All of the proposed activities that may
disturb sea otters will occur simultaneously with in-water activities
that do generate sound. For example, operation of heavy equipment on
barge platforms will facilitate underwater pile driving. The otters
affected by the equipment operations are the same as those affected by
the pile driving. Sound exposure and behavioral disturbances are
accumulated over a 24-hour period, resulting in estimation of one
exposure from all in-water sources rather than one each from equipment
operations and pile-driving noise.
Predicting Behavioral Response Rates
Although we cannot predict the outcome of each exposure of a sea
otter to the sounds, equipment, and vessels used for the proposed
activities, it is possible to consider the most likely reactions.
Whether an individual animal responds behaviorally to such exposure is
dependent upon many variables. The health, physiological state,
reproductive state, and temperament of the individual animals will have
an effect. Factors such as the activity of the animal, exposure to
other disturbances, habituation of the animal to similar disturbances,
and the presence of predators, pups, or other otters will have an
effect as well. We assumed all animals exposed to underwater sound
levels that meet acoustic criteria would experience Level B harassment.
Distances to Thresholds
The total take of sea otters for each of the proposed construction
projects in Sitka Sound and Port Frederick was estimated by calculating
the number of otters in the ensonified areas during the full duration
of the projects. To calculate the areas that will be ensonified during
each component of the projects, we first estimated the distances that
underwater sound will travel before attenuating to levels below
thresholds for take by Level A and Level B harassment. The distances to
the Level A thresholds were calculated using the NMFS Acoustical
Guidance Spreadsheets (NMFS 2018b) and their thresholds for otariid
pinnipeds as a proxy for sea otters. Distances to the 160-dB Level B
threshold were calculated using a practical spreading transmission loss
model (15 LogR).
Model estimates incorporated operational and environmental
parameters for each activity, and characteristics of the sound produced
are shown in table 3. Weighting factor adjustments were used for SEL
calculations based on NMFS Technical Guidance (NMFS 2018a). Operational
parameters were estimated from the description of activities outlined
in the applicants' petitions.
Table 3--Assumptions Used in Calculating Distances to Level A and Level B Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source level Source Pulse
Activity Type of source \1\ WFA \2\ velocity duration Repetition rate Duration per day
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving (16-inch Stationary 181.3 dBPK @10 2 kHz........ N/A.......... N/A.......... 30 strikes/pile <=0.1 hrs/day.
piles). impulsive. m (168.2 dBSEL
@10 m).
Vibratory pile driving (16- Stationary non- 161 @10 m...... 2.5 kHz...... N/A.......... N/A.......... N/A............ 1 hr/day.
inch piles). impulsive.
Socket drilling............. Stationary non- 189.8 @1 m..... 2.5 kHz...... N/A.......... N/A.......... N/A............ 6 hrs/day.
impulsive.
Crew skiff.................. Mobile non- 175 @1 m....... 1.5 kHz...... 1.54 m/s..... N/A.......... N/A............ <1 hr/day.
impulsive.
Barge handling skiff........ Stationary non- 180 @1 m....... 1.5 kHz...... N/A.......... N/A.......... N/A............ 3 hrs/day.
impulsive.
Impact pile driving (36-inch Stationary 198.6 dBPK @10 2 kHz........ N/A.......... N/A.......... 100 strikes/ 400 strikes/day.
piles). impulsive. m (186.7 dBSEL pile.
@10 m).
Impact pile driving (42-inch Stationary 198.6 dBPK @10 2 kHz........ N/A.......... N/A.......... 135 strikes/ 370 strikes/day.
piles). impulsive. m (186.7 dBSEL pile.
@10 m).
Vibratory pile driving (24- Stationary non- 161.9 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 0.7 hrs/day.
inch piles). impulsive.
Vibratory pile driving (30- Stationary non- 161.9 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 2 hrs/day.
inch temporary piles). impulsive.
Vibratory pile removal (30- Stationary non- 161.9 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 1 hr/day.
inch temporary piles). impulsive.
[[Page 32939]]
Vibratory pile driving (30- Stationary non- 161.9 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 1 hr/day.
inch piles). impulsive.
Vibratory pile driving (36- Stationary non- 168.2 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 1 hr/day.
inch piles). impulsive.
Vibratory pile driving (42- Stationary non- 161.9 @10 m.... 2.5 kHz...... N/A.......... N/A.......... N/A............ 2 hrs/day.
inch piles). impulsive.
Socket and anchor drilling.. Stationary non- 189.8 @1 m..... 2.5 kHz...... N/A.......... N/A.......... N/A............ 4 hrs/day.
impulsive.
Crew skiff.................. Mobile non- 175 @1 m....... 1.5 kHz...... 1.54 m/s..... N/A.......... N/A............ <1 hr/day.
impulsive.
Monitoring skiff............ Mobile non- 175 @1 m....... 1.5 kHz...... 1.54 m/s..... N/A.......... N/A............ 12 hrs/day.
impulsive.
Barge handling skiff........ Stationary non- 180 @1 m....... 1.5 kHz...... N/A.......... N/A.......... N/A............ 3 hrs/day.
impulsive.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Source level is given in dBrms re 1 [micro] Pa, unless otherwise indicated, as measured at the given distance from the source in meters.
\2\ Weighting factor adjustment.
The distances to the modelled Level A and Level B thresholds are
shown in table 4. Each estimate represents the radial distance away
from the sound source within which an otter exposed to the sound of the
activity is expected to experience take by Level A or Level B
harassment.
Table 4--Calculated Distance in Meters (m) to Level A and Level B Thresholds
----------------------------------------------------------------------------------------------------------------
Level A--NMFS Otariid Level B--
------------------------------------------------ USFWS
Impulsive Non- impulsive ---------------
Applicant Activity ------------------------------------------------ Both
---------------
232 dB peak 203 dB SEL 219 dB SEL 160 dB rms
----------------------------------------------------------------------------------------------------------------
City and Borough of Sitka..... Impact pile 0.0 0.4 .............. 263.0
driving (16-
inch piles).
Vibratory pile .............. .............. 0.3 11.7
driving/removal
(16-inch piles).
Socket drilling. .............. .............. 8.0 97.0
Crew skiff...... .............. .............. 0.6 10.0
Barge handling .............. .............. 1.5 21.5
skiff.
Duck Point Development, LLC Impact pile 0.0 37.3 .............. 3,744.0
for Hoonah. driving (36- 0.0 28.7 3,744.0
inch piles).
Impact pile
driving (42-
inch piles).
Vibratory pile .............. .............. 0.3 13.4
driving (24-
inch piles).
Vibratory pile .............. .............. 0.5 13.4
driving (30-
inch temporary
piles).
Vibratory pile .............. .............. 0.3 13.4
removal (30-
inch temporary
piles).
Vibratory pile .............. .............. 0.3 13.4
driving (30-
inch piles).
Vibratory pile .............. .............. 0.9 35.2
driving (36-
inch piles).
Vibratory pile .............. .............. 1.4 35.2
driving (42-
inch piles).
Socket and .............. .............. 9.7 97.0
anchor drilling.
Crew skiff...... .............. .............. 0.6 10.0
Monitoring skiff .............. .............. 0.6 10.0
Barge handling .............. .............. 1.5 21.5
skiff.
----------------------------------------------------------------------------------------------------------------
Estimates of Take
To calculate the areas that will be ensonified by pile driving, we
used either half or all of the area of the circle of the radii in table
4, above, depending on the size of the radius. Pile driving will take
place close to shore; however, many of the radii are small enough that
their defined circles will fall entirely, or nearly entirely, in the
water, especially at higher tides--in these instances, the area was
calculated as [pi] r\2\. The exceptions are the Level B radii for
impact installation of the 36- and 42-inch piles at Hoonah; for these
we used half of the area of the circle, or \1/2\ [pi] r\2\.
The areas ensonified by crew and monitoring vessel operations were
estimated by multiplying the vessels' anticipated daily track length by
twice the 160-dB radius plus [pi] r\2\ to account for the rounded ends
of the track line. Based on the figures provided in the applicants'
proposals and discussions with the contractors, it was estimated that
each trip would be no more than 500 m (1,640 ft); six trips per day are
expected for the crew vessel at Sitka, and eight trips per day are
expected for the crew vessel at Hoonah. For the monitoring skiff, the
track length was estimated by multiplying running time by vessel speed:
12 hours per day by 20 km per hour or about 10 knots, plus the rounded
end of the track line as described above. The barge handling
[[Page 32940]]
skiff will be stationary, so the ensonified area is simply the area of
the circle defined by the 160 dB radius, [pi] r\2\.
We then took two approaches to estimate the number of otters that
may be present within the areas that will be ensonified by the various
sound sources. We used densities of otters based on recent analyses of
data from aerial and skiff-based surveys conducted by the Service and
USGS in southeast Alaska. The most recently available estimates of the
distribution and abundance of northern sea otters in southeast Alaska
indicate that the density of animals in Sitka Sound is 0.842 otters per
km\2\; in the Port Frederick area the density is estimated at 0.368
animals per km\2\ (Tinker et al., in press). To estimate the expected
numbers of animals exposed to noise levels at or above the Level A and
Level B thresholds, we multiplied the ensonified areas by the density
of otters and the number of days for each activity. For the Sitka
project, this resulted in an estimate of zero exposures of northern sea
otters to noise levels exceeding Level A thresholds and 0.252 exposures
of northern sea otters to noise levels exceeding Level B thresholds
(table 5). For the Hoonah project, the estimates are 0.012 Level A
takes and 199.888 Level B takes (table 5). The only operations with the
potential for take by Level A harassment are impact pile driving of 36-
and 48-inch piles. The application of shutdown measures (see Measures
to Reduce Impact, below) will eliminate the possibility of otters being
exposed to sounds in excess of Level A thresholds. No authorization of
take by Level A harassment is being requested, none is expected, and
none will be authorized.
Table 5--Estimate of Total Take for Each Proposed Activity Based on Estimates Derived From Northern Sea Otter Densities in the Project Areas. These
Estimates Do Not Account for Avoidance of Take by the Application of Proposed Mitigation Measures
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
---------------------------------------------------
Number of Duration Impulsive Non-
Applicant Activity piles (days) -------------------------- impulsive ------------
-------------
232 pk 203 SEL 219 SEL 160 rms
--------------------------------------------------------------------------------------------------------------------------------------------------------
City and Borough of Sitka.................. Impact pile driving (16-inch 6 1 0.000 0.000 ........... 0.183
piles).
Vibratory pile driving (16- 6 1 ........... ........... 0.000 0.000
inch piles).
Socket drilling.............. ........... 2 ........... ........... 0.000 0.000
Crew skiff................... ........... 3 ........... ........... 0.000 0.067
Barge handling skiff......... ........... 3 ........... ........... 0.000 0.002
-----------------------------------------------------------------------------
Total.................................. ............................. ........... 3 0.000 0.000 0.000 0.252
--------------------------------------------------------------------------------------------------------------------------------------------------------
DPD/Hoonah Berth II........................ Impact pile driving (36-inch 16 4 0.000 0.006 ........... 32.411
piles).
Impact pile driving (42-inch 8 4 0.000 0.006 ........... 32.411
piles).
Vibratory pile driving (24- 24 4.5 ........... ........... 0.000 0.000
inch piles).
Vibratory pile driving (30- 62 10.5 ........... ........... 0.000 0.002
inch temporary piles).
Vibratory pile removal (30- 62 10.5 ........... ........... 0.000 0.002
inch temporary piles).
Vibratory pile driving (30- 3 1.5 ........... ........... 0.000 0.000
inch permanent piles).
Vibratory pile driving (36- 16 8 ........... ........... 0.000 0.006
inch piles).
Vibratory pile driving (42- 8 4 ........... ........... 0.000 0.006
inch piles).
Socket drilling/rock ........... 28 ........... ........... 0.000 0.304
anchoring.
Crew skiff................... ........... 75 ........... ........... 0.000 2.217
Monitoring skiff............. ........... 75 ........... ........... 0.000 132.489
Barge handling skiff......... ........... 75 ........... ........... 0.000 0.040
-----------------------------------------------------------------------------
Total.................................. ............................. ........... 75 0.000 0.012 0.000 199.888
--------------------------------------------------------------------------------------------------------------------------------------------------------
In the calculation of otter densities, sightings data from transect
surveys are averaged over a large area. While densities provide the
most reliable estimates of animal presence within a relatively large
subset of the area for which density was calculated, they do not
account for patchy distribution of animals within relatively small
areas. For each project area considered here, local knowledge suggests
that sea otter utilization of some areas of habitat near the
construction sites is greater than indicated by density data. The
estimates of take based on density (table 5) almost certainly
underestimate the number of otters likely to be affected by the
activities planned for each location.
Solstice Alaska Consulting, Inc. conducted surveys of the Sitka
O'Connell Bridge site; the data collected suggest that between one and
four sea otters can be expected near the project area daily (Solstice
Alaska Consulting Inc., unpublished data). We therefore assumed that 4
animals would be present on each of the 3 days of operations.
The Hoonah Indian Association, based on local knowledge and in
consultation with Solstice Alaska Consulting Inc., indicated that
between one and six sea otters would likely be
[[Page 32941]]
near the project area daily. Communications among Service staff
indicated that group sizes at Cannery Point can be larger--frequently
10 animals (Michelle Kissling, USFWS, pers. comm.). We assumed that a
group of 10 otters would be present each day in the immediate project
vicinity at Hoonah. Additionally, the Hoonah Indian Association
indicated that larger rafts of otters, up to 60 individuals, are
sighted regularly near Halibut Island, which lies within the Level B
zone of acoustical influence for impact pile driving for the DPD
project. For the purposes of estimating take, we therefore assumed that
60 individuals would be present at Halibut Island on each day during
the project.
With this information in mind, we made a second estimate of take by
Level B harassment by multiplying the number of otters expected to be
in the Level B harassment zone by the number of days of operations
(table 6). For the CBS project, operations are expected to take place
on 3 days and result in the take of four otters each day. Four otters
multiplied by 3 days results in 12 takes of otters.
The total number of days of operations for the DPD project is 75.
However, the number of potentially affected otters on a given day is
dependent upon which operations are undertaken. During the 8 days of
impact pile driving at Hoonah, the area in which noise levels will
exceed the Level B harassment threshold is likely to contain 70 sea
otters:--10 animals within the immediate vicinity of Hoonah and 60
animals near Halibut Island. On the other 67 days of pile-driving
operations, the Level B harassment zone does not reach Halibut Island,
and would contain only the 10 animals expected to be present in the
immediate vicinity of Cannery Point. On all 75 days of operations, the
monitoring skiff will be operating well outside the areas defined by
the 160-dB zone for pile-driving operations, and so the density
approach was applied to estimating take for this larger area. Sea
otters may be encountered within the 160-dB radius created by the
skiff's motor (10 m or 33 ft). We estimated a Level B harassment of two
sea otters per day for the operation of the monitoring skiff based on
the density approach (above). The total number of Level B exposures for
the DPD/Hoonah Berth II project is 1,380 (table 6).
Table 6--Estimate of Total Take for Each Proposed Activity Based on Estimates Derived From Northern Sea Otter
Group Sizes in the Project Areas
----------------------------------------------------------------------------------------------------------------
Number of
Duration Level B Total Level B
Applicant Activity (days) exposures per exposures
day
----------------------------------------------------------------------------------------------------------------
City and Borough of Sitka............. All..................... 3 4 12
-----------------------------------------------
Total .............. .............. 12
Duck Point Development/Hoonah Berth II Impact pile driving..... 8 70 560
Monitoring skiff........ 75 2 150
Vibratory pile driving/ 67 10 670
removal, socket
drilling, crew vessel,
barge positioning.
-----------------------------------------------
Total .............. .............. 1,380
----------------------------------------------------------------------------------------------------------------
For the CBS project at O'Connell Bridge, we assumed that the four
animals present on each day would likely be the same individuals from
day to day. We therefore estimate that there would be 12 exposures of 4
northern sea otters to sounds in excess of the threshold for take by
Level B harassment.
For the DPD/Hoonah Berth II project, we assumed that the
composition of the groups at Cannery Point and Halibut Island would
remain static but that two different individuals would be encountered
by the monitoring skiff on each day of surveys of the waters of Port
Frederick and Icy Strait. Thus, the number of individuals affected
would be 10 + 60 + (2 x 75) = 220 otters.
Critical Assumptions
We propose to authorize up to 12 takes of 4 sea otters by Level B
harassment from the CBS project. For the DPD/Hoonah Berth II project,
we propose to authorize up to 1,380 takes of 220 northern sea otters.
We made several critical assumptions to conduct this analysis. We
assumed that take by harassment equated to exposure to noise meeting or
exceeding the specified criteria. We also assumed all otters exposed to
these noise levels would exhibit behavioral responses that indicate
harassment or disturbance. We assumed the response rates are uniform
throughout the population, though there are likely to be some animals
that respond more to disturbance and some less. Our estimates also do
not account for variable responses by age and sex. There is not enough
information available to develop a correction factor for these
differences; therefore, a correction factor was not applied. This will
result in overestimation in take calculations from exposure to
underwater noise and underestimation of take from all other sources.
The degree of over- or under-estimation of take is unknown.
The estimate of behavioral responses do not account for the
variability of movements of animals in the project area. Our assessment
assumes that the animals near Sitka, Cannery Point, and Halibut Island
will remain, i.e., the individual composition of the affected groups of
sea otters will not change. Conversely, we assume that otters
encountered in the waters of Port Frederick and Icy Strait will be
transitory, i.e., different individual animals each day. There is not
enough information about the movement of sea otters in response to
specific disturbances to refine these assumptions. While otters do have
smaller home ranges than other marine mammals, and those in the project
area are likely to be exposed to sound during multiple days of work, it
is unlikely that any single otter will continue to respond in the same
manner. The otter will either leave the area then return after
activities are complete, or it will habituate to the disturbance.
However, we have no data to adjust for the likelihood of departure or
habituation. This situation is likely to result in overestimation of
take.
We do not account for an otter's time at the water's surface where
sound attenuates faster than in deeper water. The average dive time of
a northern sea otter is only 85 to 149 seconds (Bodkin et al. 2004;
Wolt et al. 2012). Wolt et al.
[[Page 32942]]
(2012) found Prince William Sound sea otters average 8.6 dives per
feeding bout, and when multiplied by the average dive time (149 sec),
the average total time a sea otter spends underwater during a feeding
bout is about 21 minutes. Bodkin et al. (2007) found the overall
average activity budget (proportion of 24-hour day) spent foraging and
diving was 0.48 (11.4 hours per day), and 0.52 nondiving time (12.5
hours per day). Gelatt et al. (2002) found that the percent time
foraging ranged from 21 percent for females with very young (less than
3 weeks of age) dependent pups to 52 percent for females with old
(greater than or equal to 10 weeks of age) pups. Therefore, although
exposure to underwater sound during a single dive is limited,
accumulation of exposure over time is expected. Our assessment will
cause some overestimation in this regard.
We also assume that the mitigation measures presented will be
effective for eliminating take by Level A harassment and reducing take
by Level B harassment. Given that the largest Level A radius is
slightly under 40 m (131 ft), it is reasonable to expect that visual
monitoring and mitigation will be effective in this regard. However,
additional information is needed to quantify the effectiveness of
mitigation. The monitoring and reporting in these proposed IHAs will
help fill this information need in the future, but for this suite of
proposed activities, no adjustments were made to estimate the number of
Level B takes that will be avoided by applying effective mitigation
measures.
Potential Impacts on the Southeast Alaska Sea Otter Stock
The estimated level of take by Level B harassment is small relative
to the most recent stock abundance estimates for the southeast Alaska
stock of northern sea otter, which is 25,712 animals (USFWS 2014). The
take of animals associated with the CBS project is less than 0.1
percent of the current population size (4 / 25,712 [ap] 0.0002). For
the DPD project, the take of 220 animals is about 0.9 percent of the
southeast Alaska stock (220 / 25,712 [ap] 0.0086).
Potential Impacts on Subsistence Uses
Sea otter subsistence harvest by Alaska Natives from the villages
of Sitka and Hoonah occurs year-round in areas relatively near the
proposed project areas. Between 2013 and 2017, Alaska Native residents
of Sitka harvested approximately 1,541 sea otters averaging 257 per
year (although numbers from 2018 are preliminary). Over the same
period, Alaska Native residents of Hoonah harvested 394 animals,
averaging 67 per year.
The applicants' activities will not preclude access to hunting
areas or interfere in any way with individuals wishing to hunt. Pile
driving and vessel use may displace otters, resulting in changes to
availability of otters for subsistence use during the project period.
Otters may be more vigilant during periods of disturbance, which could
affect hunting success rates. The applicants have coordinated with the
Indigenous People's Council for Marine Mammals, the Alaska Sea Otter
and Steller Sea Lion Commission, the Hoonah Indian Association, and the
Sitka Tribe of Alaska to identify and avoid potential conflicts. The
applicants reported that no conflicts with sea otter subsistence
harvest were identified by these groups.
Findings
We propose the following findings regarding these actions:
Small Numbers
For small numbers analyses, the statute and legislative history do
not expressly require a specific type of numerical analysis, leaving
the determination of ``small'' to the agency's discretion. In this
case, we propose a finding that the applicants' projects may result in
takes from the southeast stock as follows: The take of 4 sea otters for
CBS and 220 sea otters for DPD. The current estimate of the southeast
Alaska stock of northern sea otters is 25,712 animals (USFWS 2014). The
number of animals taken associated with the CBS project represent 0.02
percent of the stock. For the DPD project, the number of animals taken
represent 0.86 percent of the stock. Based on these numbers, we propose
a finding that the applicants' projects will take a small number of
animals.
Negligible Impact
We propose a finding that the incidental take by harassment
resulting from the proposed project 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 would,
therefore, have no more than a negligible impact on the southeast
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 potential sources of disturbance
caused by the project; and the potential responses of animals to this
disturbance. In addition, we reviewed materials supplied by the
applicants, other operators in Alaska, our files and datasets,
published reference materials, and species experts.
Otters are likely to respond to proposed activities with temporary
behavioral modification or displacement. These reactions are unlikely
to have consequences for the health, reproduction, or survival of
affected animals. The areas in which sound production is expected to
reach levels capable of causing harm are small and we expect visual
monitoring to eliminate this risk, so Level A harassment is not
anticipated and not authorized. 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. Some animals may exhibit more acute
responses typical of Level B harassment, such as fleeing, ceasing
feeding, or flushing from a haulout. These responses could have
significant biological impacts for a few affected individuals, but most
animals will also tolerate this type of disturbance without lasting
effects. We do not expect this type of harassment to affect annual
rates of recruitment or survival or result in adverse effects on the
species or stock.
Our proposed finding of negligible impact applies to incidental
take associated with the proposed activities as mitigated by the
avoidance and minimization measures identified in the applicants'
mitigation and monitoring plans. These measures are designed to reduce
interactions with and impacts to otters. Mitigation, monitoring, and
reporting procedures are required for the validity of our findings and
are a necessary component of the IHAs. For these reasons, we propose
findings that the CBS and DPD projects will have a negligible impact on
the southeast Alaska stock of sea otters.
Impact on Subsistence
We propose a finding that the anticipated harassment caused by both
applicants' activities would not have an unmitigable adverse impact on
the availability of sea otters for taking for subsistence uses. In
making this finding, we considered the timing and location of the
proposed activities and the location of subsistence harvest activities
in the area of the proposed project. We also considered both
applicants' consultations with subsistence
[[Page 32943]]
communities and commitment to development of a Plan of Cooperation
(POC), should any adverse impacts be identified.
Required Determinations
National Environmental Policy Act (NEPA)
We have prepared draft environmental assessment in accordance with
the NEPA (42 U.S.C. 4321 et seq.). We have preliminarily concluded that
approval and issuance of the authorizations for the nonlethal,
incidental, unintentional take by Level B harassment of small numbers
of the southeast Alaska stock of northern sea otters in Sitka Sound and
Port Frederick, during activities conducted by the applicants in 2019,
would not significantly affect the quality of the human environment,
and that the preparation of an environmental impact statement for these
actions is not required by section 102(2) of NEPA or its implementing
regulations. We are accepting comments on these draft environmental
assessments as described above in ADDRESSES.
Endangered Species Act (ESA)
The proposed authorization has no effect on any species listed as
threatened or endangered under the ESA.
Government-to-Government Coordination
It is our responsibility to communicate and work directly on a
Government-to-Government basis with federally recognized Alaska Native
tribes and corporations 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 Natives. 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 Secretarial 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 proposed activities on
federally recognized Alaska Native Tribes and corporations. Through the
IHA process identified in the MMPA, the applicants have presented a
communication process, culminating in a POC if needed, with the Native
organizations and communities most likely to be affected by their work.
The applicants have engaged these groups in informational meetings.
Proposed Authorization
The Service proposes to issue an IHA to the CBS for up to 12
incidental takes by Level B harassment of 4 northern sea otters from
the southeast Alaska stock. We also propose to issue an IHA to DPD for
up to 1,380 incidental takes by Level B harassment of 220 sea otters.
Authorized take will be limited to disruption of behavioral patterns
that may be caused by pile driving and vessel operations conducted by
the applicants in Sitka Sound and Port Frederick/Icy Strait, Alaska,
during the time period of July 22, 2019, through December 31, 2019.
Take by injury or death to northern sea otters resulting from these
construction activities and vessel operations is neither anticipated
nor authorized.
The final IHA will incorporate the mitigation, monitoring, and
reporting requirements provided below. The applicants would be
responsible for following these requirements. These authorizations
would not allow the intentional taking of sea otters.
A. General Conditions for Issuance of the Proposed IHAs
1. The taking of sea otters whenever the required conditions,
mitigation, monitoring, and reporting measures are not fully
implemented as required by the IHAs will be prohibited. Failure to
follow measures specified may result in the modification, suspension,
or revocation of the IHA.
2. If take exceeds the level or type identified in the proposed
authorization (e.g., greater than 12 incidents of take of sea otters by
Level B harassment for CBS; greater than 1,380 incidents of take of sea
otters by Level B harassment for DPD (including separation of a mother
from young; injury; or death), the IHA will be invalidated and the
Service will reevaluate its findings. If project activities cause
unauthorized take, the applicant 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's MMM within 48 hours; and (iii) suspend
further activities until the Service has reviewed the circumstances,
determined whether additional mitigation measures are necessary to
avoid further unauthorized taking, and notified the applicant that it
may resume project activities.
3. All operations managers and vessel operators must receive a copy
of the 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. The IHA will apply to activities associated with the proposed
project as described in this document and in the applicants' amended
applications (Solstice Alaska Consulting, Inc., 2019a, and b). Changes
to the proposed project without prior authorization may invalidate the
IHA.
5. The applicants' IHA applications will be approved and fully
incorporated into the IHAs, unless exceptions are specifically noted
herein or in the final IHAs.
The CBS application includes these items: The applicant's original
request for an IHA, dated November 12, 2018; the applicant's response
to a request for additional information from the Service, dated March
19, 2019; the amended application, dated March 21, 2019; the
applicant's response to a request for additional information from the
Service, dated March 25, 2019; and the Marine Mammal Monitoring and
Mitigation Plan prepared by Solstice Alaska Consulting, Inc. (2019b).
The DPD application includes the following items: The applicant's
original request for an IHA, dated January 30, 2019; the applicant's
response to a request for additional information from the Service,
dated March 19, 2019; the amended application, dated March 21, 2019;
and the Marine Mammal Monitoring and Mitigation Plan prepared by
Solstice Alaska Consulting, Inc. (2019a).
6. Operators will allow Service personnel or the Service's
designated representative to visit project work sites to monitor
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 applicants'
authority, including all contractors and subcontractors.
B. Avoidance and Minimization
1. Shutdown and monitoring zones will be established as shown in
Table 7.
[[Page 32944]]
Table 7--Shutdown and Monitoring Zones by Activity Type
----------------------------------------------------------------------------------------------------------------
Level A Level B
shutdown zone monitoring
Applicant Activity (radius in zone (radius
meters) in meters)
----------------------------------------------------------------------------------------------------------------
City and Borough of Sitka.................. Impact pile driving (16-inch piles) 10 265
Vibratory pile driving (16-inch 10 15
piles).
Socket and anchor drilling......... 15 100
Crew skiff......................... 10 100
Barge handling skiff............... 10 25
Duck Point Development, LLC/Hoonah Berth II Impact pile driving (36-inch piles) 50 3,745
Impact pile driving (42-inch piles) 50 3,745
Vibratory pile driving (24-inch 10 25
piles).
Vibratory pile driving (30-inch 10 25
temporary piles).
Vibratory pile removal (30-inch 10 25
temporary piles).
Vibratory pile driving (30-inch 10 25
piles).
Vibratory pile driving (36-inch 10 50
piles).
Vibratory pile driving (42-inch 10 50
piles).
Socket and anchor drilling......... 15 100
Crew skiff......................... 10 100
Monitoring skiff................... 10 100
Barge handling skiff............... 10 25
----------------------------------------------------------------------------------------------------------------
2. Vessels will not approach within 100 m (328 ft) of individual
sea otters or 500 m (1,640 ft) of groups of 10 or more otters.
Operators will reduce vessel speed if a sea otter approaches or
surfaces within 100 m (328 ft) of a vessel.
3. All vessels must avoid areas of active or anticipated
subsistence hunting for sea otters as determined through community
consultations.
C. Monitoring
1. Trained and qualified PSOs will be placed at positions with good
vantage of shutdown and monitoring zones for pile-driving activities to
perform the monitoring of sea otters necessary for initiation of
adaptive mitigation measures.
2. A trained and qualified PSO will be placed on the vessel used to
monitor the Level B harassment zones defined in these IHAs and in any
IHAs issued by the NMFS to perform the monitoring of sea otters
necessary for initiation of adaptive mitigation measures.
3. While on shift, PSOs will have no primary duties other than to
watch for and report on events related to marine mammals.
D. Measures To Reduce Impacts to Subsistence Users
Prior to conducting the work, applicants will take the following
steps to reduce potential effects on subsistence harvest of sea otters:
(i) Avoid work in areas of known subsistence harvest of sea otters;
(ii) discuss the planned activities with subsistence stakeholders
including Sitka Sound and Port Frederick villages, traditional
councils, and harvest commissions; (iii) identify and work to resolve
concerns of stakeholders regarding the project's effects on subsistence
hunting of sea otters; and (iv) if any unresolved or ongoing concerns
remain, develop a POC in consultation with the Service and subsistence
stakeholders to address these concerns.
E. Reporting Requirements
1. The applicants must notify the Service at least 48 hours prior
to commencement of activities.
2. Reports will be submitted to the Service's MMM weekly during
project activities. The reports will summarize project work and
monitoring efforts.
3. A final report will be submitted to the Service's MMM within 90
days after the expiration of the IHAs. It will include a summary of
monitoring efforts and observations. All project activities will be
described, along with any additional work yet to be done. Factors
influencing visibility and detectability of marine mammals (e.g., sea
state, number of observers, fog, and glare) will be discussed. The
report will describe changes in sea otter behavior resulting from
project activities and any specific behaviors of interest. Sea otter
observation records will be provided in the form of an electronic
database or spreadsheet files. The report will assess any effects that
operations may have had on the availability of sea otters for
subsistence harvest and, if applicable, evaluate the effectiveness of
the POC for preventing impacts to subsistence users of sea otters.
4. Injured, dead, or distressed sea otters that are associated with
project activities must be reported to the Service MMM within 48 hours
of discovery. Injured, dead, or distressed sea otters that are not
associated with project activities (e.g., animals found outside the
project area, previously wounded animals, or carcasses with moderate to
advanced decomposition, or scavenger damage) do not need to be reported
to the Service. Photographs, video, location information, or any other
available documentation shall be provided to the Service.
5. If behaviors indicative of Level B harassment are observed
during the course of pile driving or vessel operations, the PSO will
record the details regarding the behavior(s) and the distance(s) at
which the animals showed behaviors indicative of harassment. If such
incidences take place at distances greater than the standoff and
shutdown radii described above in Avoidance and Minimization, this
information will be reported to the Service's MMM within 24 hours; the
Service MMM will evaluate the information and determine whether
adjustment of the standoff or shutdown distance is appropriate.
6. All reports shall be submitted by email to
fw7_mmm_reports@fws.gov.
7. Applicants must notify the Service upon project completion or
end of the work season.
References
A list of the references cited in this notice is available at
www.regulations.gov in Docket No. FWS-R7-ES-2019-0053.
Request for Public Comments
If you wish to comment on these proposed IHAs, the associated draft
environmental assessments, or both, you
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may submit your comments by any of the methods described in ADDRESSES.
Please identify if you are commenting on the proposed IHAs (and which
IHA), draft environmental assessments (and which environmental
assessment), or both (IHAs and environmental assessments), make your
comments as specific as possible, confine them to issues pertinent to
the proposed authorization(s), 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).
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.
Dated: May 30, 2019.
Gregory E. Siekaniec,
Regional Director, Alaska Region.
[FR Doc. 2019-14667 Filed 7-9-19; 8:45 am]
BILLING CODE 4333-15-P