Notice2021-16861
Taking of Marine Mammals Incidental to Specific Activities; Taking of Marine Mammals Incidental to Pile Driving and Removal Activities During the Metlakatla Seaplane Facility Refurbishment Project, Metlakatla, Alaska
Primary source
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Published
August 6, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an incidental harassment authorization (IHA) to the Alaska Department of Transportation and Public Facilities (AKDOT&PF) to incidentally harass, by Level B harassment only, marine mammals during pile driving/removal and down-the-hole drilling (DTH) activities for maintenance improvements to the existing Metlakatla Seaplane Facility (MSF) in Southeast Alaska.
Full Text
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[Federal Register Volume 86, Number 149 (Friday, August 6, 2021)]
[Notices]
[Pages 43190-43204]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-16861]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XB234]
Taking of Marine Mammals Incidental to Specific Activities;
Taking of Marine Mammals Incidental to Pile Driving and Removal
Activities During the Metlakatla Seaplane Facility Refurbishment
Project, Metlakatla, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the Alaska Department of Transportation and Public Facilities
(AKDOT&PF) to incidentally harass, by Level B harassment only, marine
mammals during pile driving/removal and down-the-hole drilling (DTH)
activities for maintenance improvements to the existing Metlakatla
Seaplane Facility (MSF) in Southeast Alaska.
DATES: This Authorization is effective for one year from issuance.
FOR FURTHER INFORMATION CONTACT: Stephanie Egger, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-alaska-department-transportation-metlakatla-seaplane-facility">https://www.fisheries.noaa.gov/action/incidental-take-authorization-alaska-department-transportation-metlakatla-seaplane-facility</a>. In case of
problems accessing these documents, or for anyone who is unable to
comment via electronic mail, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et
[[Page 43191]]
seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow,
upon request, the incidental, but not intentional, taking of small
numbers of marine mammals by U.S. citizens who engage in a specified
activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
Summary of Request
On August 10, 2020, NMFS received a request from the AKDOT&PF for
an IHA to take marine mammals incidental to pile driving/removal and
DTH activities during maintenance improvements to the existing MSF in
Southeast Alaska. The application was deemed adequate and complete on
November 23, 2020. The applicant also provided an addendum to their
application on February 23, 2021 for the addition of eight piles, some
changes to their shutdown zones, and minor changes to their take
estimates due to the increase of in-water work days from the eight
additional piles. The applicant's request is for take of eight species
of marine mammals by Level B harassment only. Neither the AKDOT&PF nor
NMFS expects serious injury or mortality to result from this activity
and, therefore, an IHA is appropriate.
Description of Planned Activity
The purpose of this project is to make repairs to the MSF. The
existing facility has experienced deterioration in recent years and
AKDOT&PF has conducted several repair projects. The facility is near
the end of its useful life, and replacement of all the existing float
structures is required to continue safe operation in the future. The
planned project in Metlakatla is located approximately 24 kilometers
(km) (15 miles (mi)) south of Ketchikan, in Southeast Alaska.
Metlakatla, is on Annette Island, in the Prince of Whales-Hyder Census
Area of Southeast Alaska. The Metlakatla Seaplane Facility is centrally
located in the village of Metlakatla on the south shore of Port
Chester.
The planned project includes pile driving/removal and DTH over 2
months (approximately 26 working days) beginning in August 2021. Pile
installation and removal will be intermittent during this period,
depending on weather, construction and mechanical delays, protected
species shutdowns, and other potential delays and logistical
constraints. Pile installation will occur intermittently during the
work period, for durations of minutes to hours at a time. Approximately
18 days of pile installation and 8 days of pile removal will occur
using vibratory and impact pile driving and some DTH to stabilize the
piles. These are discussed in further detail below. The total
construction duration accounts for the time required to mobilize
materials and resources and construct the project.
Planned activities included as part of the project with potential
to affect marine mammals include the noise generated by vibratory
removal of steel pipe piles, vibratory and impact installation of steel
pipe piles, and DTH to stabilize piles. Pile removal will be conducted
using a vibratory hammer. Pile installation will be conducted using
both a vibratory and impact hammer and DTH pile installation methods.
Piles will be advanced to refusal using a vibratory hammer. After DTH
pile installation, the final approximate 3.048 m (10 ft) of driving
will be conducted using an impact hammer so that the structural
capacity of the pile embedment can be verified. The pile installation
methods used will depend on sediment depth and conditions at each pile
location. Pile installation and removal will occur in waters
approximately 6-7 m (20-23 ft) in depth.
The project will involve the removal of 11 existing steel pipe
piles (16-inch (in) diameter) that support the existing multiple-float
structure. The multiple-float timber structure, which covers 8,600
square ft, will also be removed. A new 4,800-square-ft single-float
timber structure will be installed in the same general location. Six
24-in diameter steel pipe piles will be installed to act as restraints
for the new seaplane float. In addition, 12 temporary 24-in steel piles
will be installed to support pile installation and removed following
completion of construction.
DTH pile installation involves drilling rock sockets into the
bedrock to support installation of the 6 permanent piles and 12
temporary piles. Rock sockets consist of inserting the pile in a
drilled hole into the underlying bedrock after the pile has been driven
through the overlying softer sediments to refusal by vibratory or
impact methods. The pile is advanced farther into this drilled hole to
properly secure the bottom portion of the pile into the rock. The depth
of the rock socket varies, but 3.048-4.572 m (10-15 ft) is commonly
required. The diameter of the rock socket is slightly larger than the
pile being driven. Rock sockets are constructed using a DTH device with
both rotary and percussion-type actions. Each device consists of a
drill bit that drills through the bedrock using both rotary and pulse
impact mechanisms. This breaks up the rock to allow removal of the
fragments and insertion of the pile. The pile is usually advanced at
the same time that drilling occurs. Drill cuttings are expelled from
the top of the pile using compressed air. It is estimated that drilling
rock sockets into the bedrock will take about 1-3 hours (hrs) per pile.
Tension anchors will be installed in each of the six permanent
piles. Tension anchors are installed within piles that are drilled into
the bedrock below the elevation of the pile tip after the pile has been
driven through the sediment layer to refusal. A 6- or 8-in diameter
steel pipe casing will be inserted inside the larger diameter
production pile. A rock drill will be inserted into the casing, and a
6- to 8-in diameter hole will be drilled into bedrock with rotary and
percussion drilling methods. The drilling work is contained within the
steel pile casing and the steel pipe pile. The typical depth of the
drilled hole varies, but 20-30 ft is common. Rock fragments will be
removed through the top of the casing with compressed air. A steel rod
will then be grouted into the drilled hole and affixed to the top of
the pile. The purpose of a tension anchor is to secure the pile to the
bedrock to withstand uplift forces. It is estimated that tension anchor
installation will take about 1-2 hrs per pile.
No concurrent pile driving is anticipated for this project.
Please see Table 1 below for the specific amount of time required
to install and remove piles.
[[Page 43192]]
Table 1--Pile Driving and Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact DTH pile
strikes Vibratory DTH pile installation Total
Number of Rock Tension per pile duration installation (tension duration of Piles per Total
Pile diameter and type piles sockets anchors (duration per pile (rock socket) anchor) activity day days
in (minutes) duration per duration per per pile (range)
minutes) pile (minutes) pile (minutes) (hours)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Plumb Piles 4 4 4 20 (15) 15 180 120 5.5 0.5 (0-1) 8
(Permanent).................
24-in Steel Batter Piles 2 2 2 20 (15) 15 90 120 4 0.5 (0-1) 4
(Permanent).................
24-in Steel Piles (Temporary) 12 12 0 20 (15) 15 60 N/A 1.5 2 (1-3) 6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
16-in Steel Piles............ 11 N/A N/A N/A 30 N/A N/A 0.5 3 (2-4) 4
24-in Steel Piles (Temporary) 12 N/A N/A N/A 30 N/A N/A 0.5 3 (2-4) 4
--------------------------------------------------------------------------------------------------------------------------
Totals................... 29 18 6 N/A N/A N/A N/A N/A N/A 26
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: DTH = down-the-hole; N/A = not applicable.
A detailed description of the planned MSF project is provided in
the Federal Register notice for the proposed IHA (86 FR 34203; June 29,
2021).
Comments and Responses
A notice of NMFS' proposal to issue and IHA to AKDOT&PF was
published in the Federal Register on June 29, 2021 (86 FR 34203). That
notice described, in detail, AKDOT&PF's activity, the marine mammal
species that may be affected by the activity, and the anticipated
effects on marine mammals. During the 30-day public comment period,
NMFS received no public comments on this action.
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>) and more general information about these
species (e.g., physical and behavioral descriptions) may be found on
NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
authorized for this action, and summarizes information related to the
population or stock, including regulatory status under the MMPA and
Endangered Species Act (ESA) and potential biological removal (PBR),
where known. For taxonomy, we follow Committee on Taxonomy (2020). PBR
is defined by the MMPA as the maximum number of animals, not including
natural mortalities, that may be removed from a marine mammal stock
while allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS' SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Pacific and Alaska SARs (Carretta et al., 2020; Muto et al.,
2020). All MMPA stock information presented in Table 2 is the most
recent available at the time of publication and is available in the
2019 SARs (Caretta et al., 2020; Muto et al., 2020) and draft 2020 SARs
(available online at: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
Table 2--Marine Mammal Occurrence in the Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/SI
\1\ abundance survey) \2\ \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
Minke Whale.................... Balaenoptera Alaska................ -, -, N N/A (see SAR, N/A, see UND 0
acutorostrata. SAR).
Humpback Whale................. Megaptera novaeangliae Central N Pacific..... -, -, Y 10,103 (0.3, 7,891, 83 26
2006).
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Killer Whale................... Orcinus orca.......... Alaska Resident....... -, -, N 2,347 (N/A, 2347, 24 1
2012).
Northern Resident..... -, -, N 302 (N/A, 302, 2018).. 2.2 0.2
[[Page 43193]]
West Coast Transient.. -, -, N 349 (N/A, 349; 2018).. 3.5 0.4
Pacific White-Sided Dolphin.... Lagenorhynchus N Pacific............. -, -, N 26,880 (N/A, N/A, UND 0
obliquidens. 1990).
Family Phocoenidae (porpoises):
Dall's Porpoise................ Phocoenoides dalli.... AK.................... -, -, N 83,400 (0.097, N/A, UND 38
1991).
Harbor Porpoise................ Phocoena phocoena..... Southeast Alaska -, -, Y see SAR (see SAR, see see SAR 34
Inland waters. SAR, 2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion............... Eumetopias jubatus.... Eastern DPS........... T, D, Y 43,201 a (see SAR, 2592 112
43,201, 2017).
Family Phocidae (earless seals):
Harbor Seal.................... Phoca vitulina........ Clarence Strait....... -, -, N 27,659 (see SAR, 746 40
24,854, 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
[explain if this is the case].
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
with estimated mortality due to commercial fisheries is presented in some cases.
A detailed description of the of the species likely to be affected
by the project, including brief introductions to the species and
relevant stocks as well as available information regarding population
trends and threats, and information regarding local occurrence, were
provided in the Federal Register notice for the proposed IHA (86 FR
34203; June 29, 2021) since that time, we are not aware of any changes
in the status of these species and stocks; therefore, detailed
descriptions are not provided here. Please refer to that Federal
Register notice for these descriptions. Please also refer to NMFS'
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) for generalized
species accounts.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
Acoustic effects on marine mammals during the specified activity
can occur from vibratory and impact pile driving as well as during DTH
of the piles. The effects of underwater noise from the AKDOT&PF's
planned activities have the potential to result in Level B behavioral
harassment of marine mammals in the vicinity of the action area. The
effects of pile driving on marine mammals are dependent on several
factors, including the size, type, and depth of the animal; the depth,
intensity, and duration of the pile driving sound; the depth of the
water column; the substrate of the habitat; the standoff distance
between the pile and the animal; and the sound propagation properties
of the environment. With both types, it is likely that the pile driving
could result in temporary, short-term changes in an animal's typical
behavioral patterns and/or avoidance of the affected area. The Federal
Register notice for the proposed IHA (86 FR 34203; June 29, 2021)
included a discussion of the effects of anthropogenic noise on marine
mammals, therefore that information is not repeated here; please refer
to the Federal Register notice (86 FR 34203; June 29, 2021).
Anticipated Effects on Marine Mammal Habitat
The main impact issue associated with the planned activity would be
temporarily elevated sound levels and the associated direct effects on
marine mammals. The most likely impact to marine mammal habitat occurs
from pile driving effects on likely marine mammal prey (i.e., fish)
near where the piles are installed. Impacts to the immediate substrate
during installation and removal of piles are anticipated, but these
would be limited to minor, temporary suspension of sediments, which
could impact water quality and visibility for a short amount of time,
but which would not be expected to have any effects on individual
marine mammals. Impacts to substrate are therefore not discussed
further. These potential effects are discussed in detail in the Federal
Register notice for the proposed IHA (86 FR 34203; June 29, 2021)
therefore that information is not repeated here; please refer to that
Federal Register notice for that information.
Estimated Take
This section provides an estimate of the number of incidental takes
authorization through this IHA, which will inform both NMFS'
consideration of ``small numbers'' and the negligible impact
determination.
Except with respect to certain activities not pertinent here,
section 3(18) of the MMPA defines ``harassment'' as any act of pursuit,
torment, or annoyance, which (i) has the potential to injure a marine
mammal or marine mammal stock in the wild (Level A harassment); or (ii)
has the potential to disturb a marine mammal or marine mammal stock in
the wild by causing disruption of behavioral patterns, including, but
not limited to, migration, breathing, nursing, breeding, feeding, or
sheltering (Level B harassment).
Take of marine mammals incidental to the AKDOT&PF's pile driving
and removal activities (as well as during DTH) could occur as a result
of Level B harassment only. Below we describe how the potential take is
estimated. As described previously, no mortality is anticipated or
authorized for this
[[Page 43194]]
activity. Below we describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the planned take
estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur
permanent threshold shift (PTS) of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source (e.g., frequency, predictability, duty cycle), the environment
(e.g., bathymetry), and the receiving animals (hearing, motivation,
experience, demography, behavioral context) and can be difficult to
predict (Southall et al., 2007, Ellison et al., 2012). Based on what
the available science indicates and the practical need to use a
threshold based on a factor that is both predictable and measurable for
most activities, NMFS uses a generalized acoustic threshold based on
received level to estimate the onset of behavioral harassment. NMFS
predicts that marine mammals are likely to be behaviorally harassed in
a manner we consider Level B harassment when exposed to underwater
anthropogenic noise above received levels of 120 dB reference pressure
micro Pascal (re 1 [mu]Pa (rms)) for continuous (e.g., vibratory pile
driving and DTH) and above 160 dB re 1 [mu]Pa (rms) for impulsive
sources (e.g., impact pile driving). The AKDOT&PF's planned activity
includes the use of continuous (vibratory pile driving, DTH) and
impulsive (impact pile driving) sources, and therefore the 120 and 160
dB re 1 [mu]Pa (rms) are applicable.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise. The
technical guidance identifies the received levels, or thresholds, above
which individual marine mammals are predicted to experience changes in
their hearing sensitivity for all underwater anthropogenic sound
sources, and reflects the best available science on the potential for
noise to affect auditory sensitivity by:
[ssquf] Dividing sound sources into two groups (i.e., impulsive and
non-impulsive) based on their potential to affect hearing sensitivity;
[ssquf] Choosing metrics that best address the impacts of noise on
hearing sensitivity, i.e., sound pressure level (peak SPL) and sound
exposure level (SEL) (also accounts for duration of exposure); and
[ssquf] Dividing marine mammals into hearing groups and developing
auditory weighting functions based on the science supporting that not
all marine mammals hear and use sound in the same manner.
These thresholds were developed by compiling and synthesizing the
best available science, and are provided in Table 3 below. The
references, analysis, and methodology used in the development of the
thresholds are described in NMFS 2018 Technical Guidance, which may be
accessed at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
DTH pile installation includes drilling (non-impulsive sound) and
hammering (impulsive sound) to penetrate rocky substrates (Denes et al.
2016; Denes et al. 2019; Reyff and Heyvaert 2019). DTH pile
installation was initially thought be a primarily non-impulsive noise
source. However, Denes et al. (2019) concluded from a study conducted
in Virginia, nearby the location for this project, that DTH should be
characterized as impulsive based on Southall et al. (2007), who stated
that signals with a >3 dB difference in sound pressure level in a
0.035-second window compared to a 1-second window can be considered
impulsive. Therefore, DTH pile installation is treated as both an
impulsive and non-impulsive noise source. In order to evaluate Level A
harassment, DTH pile installation activities are evaluated according to
the impulsive criteria and using 160 dB rms. Level B harassment
isopleths are determined by applying non-impulsive criteria and using
the 120 dB rms threshold which is also used for vibratory driving. This
approach ensures that the largest ranges to effect for both Level A and
Level B harassment are accounted for in the take estimation process.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
[Auditory injury]
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
[[Page 43195]]
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
Sound Propagation
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * log<INF>10</INF>(R<INF>1</INF>/R<INF>2</INF>), where
B = transmission loss coefficient (assumed to be 15)
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log(range)). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log(range)). As is
common practice in coastal waters, here we assume practical spreading
loss (4.5 dB reduction in sound level for each doubling of distance).
Practical spreading is a compromise that is often used under conditions
where water depth increases as the receiver moves away from the
shoreline, resulting in an expected propagation environment that would
lie between spherical and cylindrical spreading loss conditions.
Practical spreading was used to determine sound propagation for this
project.
Sound Source Levels
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. There are source level
measurements available for certain pile types and sizes from the
similar environments recorded from underwater pile driving projects in
Alaska that were evaluated and used as proxy sound source levels to
determine reasonable sound source levels likely result from the
AKDOT&PF's pile driving and removal activities (Table 4). Many source
levels used were more conservative as the values were from larger pile
sizes.
Table 4--Sound Source Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile type SSL at 10 meters Literature source Federal Register sources \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Continuous (Vibratory Pile Driving and dB rms
DTH).
16-in Steel Piles........................ 161 Navy 2012, 2015............ A, B, C, H.
24-in Steel Piles........................ 161 Navy 2012, 2015............ C, D, E, H, I.
24-in DTH \b\............................ 166 Denes et al. 2016 (Table B, C, F, G.
72) \b\.
8-in DTH \c\............................. 166 NMFS \c\...................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impulsive (Impact Pile Driving and DTH) dB rms dB SEL dB Peak
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Piles........................ 193 181 210 Navy 2015.................. D, H, I.
24-in DTH \b\............................ .............. 154 .............. Denes et al. 2016 \b\......
8-in DTH \c\............................. .............. 144 170 Reyff 2020.................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Federal Register sources:
A: 84 FR 24490; May 28, 2019, City of Juneau Waterfront Improvement Project, Juneau, Alaska.
B: 85 FR 4278; January 24, 2020, Statter Harbor Improvement Project, Auke Bay, Alaska.
C: 85 FR 673; January 7, 2020, Tongass Narrows Ferry Berth Improvements, Ketchikan, Alaska.
D: 85 FR 19294; April 6, 2020, Port of Alaska's Petroleum and Cement Terminal, Anchorage, Alaska.
E: 84 FR 56767; October 23, 2019, Auke Bay Ferry Terminal Modifications and Improvements Project, Juneau, Alaska.
F: 85 FR 18196; April 1, 2020, Gastineau Channel Historical Society Sentinel Island Moorage Float Project, Juneau, Alaska.
G: 85 FR 12523; March 3, 2020, Ward Cove Cruise Ship Dock Project, Juneau, Alaska.
H: 83 FR 29749; June 26, 2018, City Dock and Ferry Terminal, Tenakee Springs, Alaska.
I: 82 FR 48987; October 23, 2017, Sand Point City Dock Replacement Project, Sand Point, Alaska.
\b\ DTH pile installation is treated as a continuous sound for Level B calculations and impulsive for Level A calculations.
\c\ Tension anchor installation (8-in DTH) is currently treated as DTH pile installation.
Notes: DTH = down-the-hole pile installation; SSL = sound source = level; dB = decibel; rms = root mean square; SEL = sound exposure level.
Level A Harassment
In conjunction with the NMFS Technical Guidance (2018), in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we
[[Page 43196]]
anticipate that isopleths produced are typically going to be
overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources (such as from
impact and vibratory pile driving and DTH), NMFS User Spreadsheet
(2020) predicts the closest distance at which, if a marine mammal
remained at that distance the whole duration of the activity, it would
not incur PTS. Inputs used in the User Spreadsheet (Tables 5 and 6),
and the resulting isopleths are reported below (Table 7).
Table 5--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Vibratory Pile
Driving
----------------------------------------------------------------------------------------------------------------
User spreadsheet input--vibratory pile driving spreadsheet Tab A.1 vibratory pile driving used
-----------------------------------------------------------------------------------------------------------------
24-in piles 24-in plumb/
16-in piles temporary batter piles
(removal) (install/ permanent
removal) (install)
----------------------------------------------------------------------------------------------------------------
Source Level (RMS SPL).......................................... 161 161 161
Weighting Factor Adjustment (kHz)............................... 2.5 2.5 2.5
Number of piles within 24-hr period............................. 4 4 4
Duration to drive a single pile (min)........................... 30 30 30
Propagation (xLogR)............................................. 15 15 15
Distance of source level measurement (meters)................... 10 10 10
----------------------------------------------------------------------------------------------------------------
Table 6--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
User spreadsheet input--impact pile driving spreadsheet tab E.1 impact pile driving used
---------------------------------------------------------------------------------------------------------------------------------------------------------
24-in piles 8-in pile 8-in pile 8-in pile 24-in pile 24-in pile 24-in pile
(permanent) (DTH) (DTH) (DTH) (DTH) (DTH) (DTH)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL)... 181 144 144 144 154 154 154
Weighting Factor Adjustment (kHz)....... 2 2 2 2 2 2 2
Number of strikes per pile.............. 20 54,000 108,000 162,000 54,000 81,000 162,000
Minutes per pile........................ .............. 60 120 180 60 90 180
Number of piles per day................. 3 1 1 1 1 1 1
Propagation (xLogR)..................... 15 15 15 15 15 15 15
Distance of source level measurement 10 10 10 10 10 10 10
(meters)...............................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 7--NMFS Technical Guidance (2020) User Spreadsheet Outputs To Calculate Level A Harassment PTS Isopleths
----------------------------------------------------------------------------------------------------------------
User spreadsheet output PTS isopleths (meters)
----------------------------------------------------------------------------------------------------------------
Level A harassment
----------------------------------------------------------------
Activity Sound source Low- Mid- High-
level at 10 m frequency frequency frequency Phocid Otariid
cetaceans cetaceans cetaceans
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
16-in steel pile removal..... 161 SPL......... 10.8 1.0 16.0 6.6 0.5
24-in steel pile temporary 161 SPL......... 10.8 1.0 16.0 6.6 0.5
installation and removal.
24-in steel pile permanent... 161 SPL......... 10.8 1.0 16.0 6.6 0.5
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
24-in steel permanent 181 SEL/193 SPL. 112.6 4.0 134.1 60.3 4.4
installation (3 piles a day).
24-in steel permanent 181 SEL/193 SPL. 85.9 3.1 102.3 46.0 3.3
installation (2 piles a day).
24-in steel permanent 181 SEL/193 SPL. 54.1 1.9 64.5 29.0 2.1
installation (1 piles a day).
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
8-in steel (60 min).......... 144 SEL/166 SPL. 35.8 1.3 42.7 19.2 1.4
8-in steel (120 min)......... 144 SEL/166 SPL. 56.9 2.0 67.8 30.4 2.2
8-in steel (180 min)......... 144 SEL/166 SPL. 74.5 2.7 88.8 39.9 2.9
24-in steel (60 min)......... 154 SEL/166 SPL. 166.3 5.9 198.1 89.0 6.5
[[Page 43197]]
24-in steel (90 min)......... 154 SEL/166 SPL. 218.0 7.8 259.6 116.6 8.5
24-in steel (180 min)........ 154 SEL/166 SPL. 346.0 12.3 412.1 185.2 13.5
----------------------------------------------------------------------------------------------------------------
Level B Harassment
Utilizing the practical spreading loss model, the AKDOT&PF
determined underwater noise will fall below the behavioral effects
threshold of 120 dB rms for marine mammals at the distances shown in
Table 8 for vibratory pile driving/removal, and DTH. With these radial
distances, the largest Level B harassment zone calculated was for DTH
at 11,659 m. For calculating the Level B harassment zone for impact
driving, the practical spreading loss model was used with a behavioral
threshold of 160 dB rms. The maximum radial distance of the Level B
harassment zone for impact piling equaled 1,585 m for 24-in piles.
Table 8 below provides all Level B harassment radial distances (m)
during the AKDOT&PF's planned activities.
Table 8--Radial Distances (Meters) to Relevant Behavioral Isopleths
------------------------------------------------------------------------
Received level at Level B harassment
Activity 10 meters (m) zone (m) *
------------------------------------------------------------------------
Vibratory Pile Driving/Removal and DTH
------------------------------------------------------------------------
16-in steel piles............... 161 SPL........... 5,415 (calculated
5,412).
24-in steel piles............... 161 SPL........... 5,415 (calculated
5,412).
8-in and 24-in DTH.............. 166 SPL........... 11,660 (calculated
11,659).
------------------------------------------------------------------------
Impact Pile Driving
------------------------------------------------------------------------
24-in steel piles............... 181 SEL/193 SPL... 1,585.
------------------------------------------------------------------------
* Numbers rounded up to nearest 5 meters. These specific rounded
distances are for monitoring purposes rather than take estimation.
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations. Potential exposures to impact pile driving, vibratory
pile driving/removal and DTH noises for each acoustic threshold were
estimated using group size estimates and local observational data. As
shown above, distances to Level A harassment thresholds for project
activities are relatively small in most cases and mitigation (i.e.,
shutdown zones) is expected to avoid Level A harassment from these
activities. Accordingly, take by Level B harassment only will be
considered for this action. Take by Level B harassment are calculated
differently for some species based on monthly or daily sightings data
and average group sizes within the action area using the best available
data.
Minke Whales
There are no density estimates of minke whales available in the
project area. These whales are usually sighted individually or in small
groups of two or three, but there are reports of loose aggregations of
hundreds of animals (NMFS 2018). Dedicated surveys for cetaceans in
Southeast Alaska found that minke whales were scattered throughout
inland waters from Glacier Bay and Icy Strait to Clarence Strait
(Dahlheim et al. 2009). All sightings were of single minke whales,
except for a single sighting of multiple minke whales. Anecdotal
observations suggest that minke whales do not enter Port Chester, and
may be more rare in the project area (L. Bethel, personal
communication, June 11, 2020 2020 as cited in the application). Based
on the potential for one group of a group size of three whales entering
the Level B harassment zone during the project, similar to what is
observed in Tongass Narrows, NMFS authorizes, take of three minke
whales over the 4-month project period by Level B harassment. No take
by Level A harassment is authorized or anticipated to occur due to
their rarer occurrence in the project area. In addition, the shutdown
zones are larger than all the calculated Level A harassment isopleths
for all pile driving/removal and DTH activities for cetaceans.
Humpback Whales
There are no density estimates for humpback whales available in the
project area. Use of Nichols Passage and Port Chester by humpback
whales is common but intermittent and dependent on the presence of prey
fish. No systematic studies have documented humpback whale abundance
near Metlakatla. Anecdotal information from Metlakatla and Ketchikan
suggest that humpback whales' utilization of the area is intermittent
year-round and local mariners estimate that one to two humpback whales
may be present in the Port Chester area on a daily basis during summer
months (L. Bethel, personal communication, June 11, 2020 2020 as cited
in the application). This is consistent with reports from Ketchikan,
which suggest that humpback whales occur alone or in groups of two or
three individuals and abundance is highest in August and September (84
FR 34134; July 17, 2019). However, anecdotal reports suggest that
humpback whale abundance is higher and occurrence is more regular in
Metlakatla. Therefore,
[[Page 43198]]
NMFS authorizes two groups of two whales, up to four individuals per
day, may be taken by Level B harassment for a total of 104 humpback
whales (4 whales per day * 26 days = 104 humpback whales).
Under the MMPA, humpback whales are considered a single stock
(Central North Pacific); however, we have divided them here to account
for distinct population segments (DPSs) listed under the ESA. Using the
stock assessment from Muto et al. 2020 for the Central North Pacific
stock (10,103 whales) and calculations in Wade et al. 2016; 9,487
whales are expected to be from the Hawaii DPS and 606 from the Mexico
DPS. Therefore, for purposes of consultation under the ESA, we
anticipate that 7 whales of the total takes would be individuals from
the Mexico DPS (104 x 0.061 = 6.3 rounded to 7). No take by Level A
harassment is authorized or anticipated to occur due to their large
size and ability to be visibly detected in the project area if an
animal should approach the Level A harassment zone as well as the size
of the Level A harassment zones, which are expected to be manageable
for the protected species observers (PSOs). The calculated Level A
isopleths for low-frequency cetaceans are 113 m or less with the
exception of DTH of limited duration of 24-in piles where they range
from 166.3-346.0 m. The shutdown zones (Table 10) are larger for all
calculated Level A harassment isopleths during all pile driving
activities (vibratory, impact and DTH) for all cetaceans.
Killer Whales
There are no density estimates of killer whales available in the
project area. Three distinct eco-types occur in Southeast Alaska
(resident, transient and offshore whales; Ford et al., 1994; Dahlheim
et al., 1997, 2008). Dahlheim et al. (2009) observed transient killer
whales within Lynn Canal, Icy Strait, Stephens Passage, Frederick
Sound, and upper Chatham Strait. As determined during a line-transect
survey by Dalheim et al. (2008), the greatest number of transient
killer whale observed in Southeast Alaska occurred in 1993 with 32
animals seen over 2 months for an average of 16 sightings per month.
Resident pods were also observed in Icy Strait, Lynn Canal, Stephens
Passage, Frederick Sound and upper Chatham Straight (Dalheim et al.
2008). Transient killer whales are often found in long-term stable
social units (pods) of 1 to 16 whales. Average pod sizes in Southeast
Alaska were 6 in spring, 5 in summer, and 4 in fall. Pod sizes of
transient whales are generally smaller than those of resident social
groups. Resident killer whales occur in pods ranging from 7 to 70
whales that are seen in association with one another more than 50
percent of the time (Dahlheim et al. 2009; NMFS 2016b). In Southeast
Alaska, resident killer whale mean pod size was approximately 21.5 in
spring, 32.3 in summer, and 19.3 in fall (Dahlheim et al. 2009). Killer
whales are observed occasionally during summer throughout Nichols
Passage, but their presence in Port Chester is unlikely. Anecdotal
local information suggests that killer whales are rarely seen within
the Port Chester area, but may be present more frequently in Nichols
Passage and other areas around Gravina Island (L. Bethel, personal
communication, June 11, 2020 2020 as cited in the application). To be
conservative NMFS authorizes one killer whale pod of up to 15
individuals once during the project could be taken by Level B
harassment based on a pod of 12 killer whales that may be present each
month similar to Tongass Narrows near Ketchikan. Additionally, a recent
monitoring report for Tongass Narrows reported 10 individuals sighted
and 10 Level B harassment takes of killer whales during May 2021. No
take by Level A harassment is authorized or anticipated to occur to the
ability to visibly detect these large whales and the small size of the
Level A harassment zones. In addition, the shutdown zones are larger
than all the calculated Level A harassment isopleths for all pile
driving/removal and DTH activities for cetaceans.
Pacific White-Sided Dolphin
There are no density estimates of Pacific white-sided dolphins
available in the project area. Most observations of Pacific white-sided
dolphins occur off the outer coast or in inland waterways near
entrances to the open ocean. Pacific white-sided dolphins have been
observed in Alaska waters in groups ranging from 20 to 164 animals,
with the sighting of 164 animals occurring in Southeast Alaska near
Dixon Entrance to the south of Metlakatla (Muto et al., 2018). In
nearby Tongass Narrows, NMFS estimated that one group of 92 Pacific
white-sided dolphin (median between 20 and 164) may occur over a period
of 1 year (85 FR 673; January 7, 2020). There are no records of this
species occurring in Port Chester, and it is uncommon for individuals
to occur in the project area. Therefore, NMFS authorizes one large
group of 92 dolphins may be taken by Level B harassment during the
project. No take by Level A harassment authorized or anticipated as the
Level A harassment isopleths are so small.
Dall's Porpoise
There are no density estimates of Dall's porpoise available in the
project area. Little information is available on the abundance of
Dall's porpoise in the inland waters of Southeast Alaska. Dall's
porpoise are most abundant in spring, observed with lower numbers in
the summer, and lowest numbers in fall. Jefferson et al., 2019 presents
abundance estimates for Dall's porpoise in these waters and found the
abundance in summer (N = 2,680, CV = 19.6 percent), and lowest in fall
(N = 1,637, CV = 23.3 percent). No systematic studies of Dall's
porpoise abundance or distribution have occurred in Port Chester or
Nichols Passage; however, Dall's porpoises have been consistently
observed in Lynn Canal, Stephens Passage, upper Chatham Strait,
Frederick Sound, and Clarence Strait (Dahlheim et al. 2009). The
species is generally found in waters in excess of 600 ft (183 m) deep,
which do not occur in Port Chester. If Dall's porpoises occur in the
project area, they will likely be present in March or April, given the
strong seasonal patterns observed in nearby areas of Southeast Alaska
(Dahlheim et al. 2009). Dall's porpoises are seen once a month or less
within Port Chester and Nichols Passage in groups of less than 10
animals (L. Bethel, personal communication, June 11, 2020 as cited in
the application).
Dall's porpoises are not expected to occur in Port Chester because
the shallow water habitat of the bay is atypical of areas where Dall's
porpoises usually occur. Therefore, NMFS authorizes one group of Dall's
porpoise (15 individuals) per month, similar to what was estimated in
nearby Tongass Narrows, may be taken by Level B harassment for a total
of 30 Dall's porpoises during the 26 days of in-water construction (2
months * 15 porpoises per month = 30). No take by Level A harassment is
authorized or anticipated to occur due to their rarer occurrence in the
project area and the unlikelihood that they would enter the Level A
harassment zone and remain long enough to incur PTS in the rare event
that they are encountered. No take by Level A harassment is authorized
or anticipated to occur, as the calculated isopleths for high-frequency
cetaceans are 134 m or less during all activities except during DTH for
24-in piles of limited duration where they are 198 m-412 m. The
shutdown zones (Table 10) are larger for all calculated Level A
harassment isopleths during all pile
[[Page 43199]]
driving activities (vibratory, impact and DTH) for all cetaceans.
Harbor Porpoise
There are no density estimates of harbor porpoise available in the
project area. Although there have been no systematic studies or
observations of harbor porpoises specific to Port Chester or Nichols
Passage, there is potential for them to occur within the project area.
Abundance data for harbor porpoises in Southeast Alaska were
collected during 18 seasonal surveys spanning 22 years, from 1991 to
2012 (Dahlheim et al. 2015). During that study, a total of 81 harbor
porpoises were observed in the southern inland waters of Southeast
Alaska, including Clarence Strait. The average density estimate for all
survey years in Clarence Strait was 0.02 harbor porpoises per square
kilometer. There does not appear to be any seasonal variation in harbor
porpoise density for the inland waters of Southeast Alaska (Dahlheim et
al. 2015). Approximately one to two groups of harbor porpoises are
observed each week in group sizes of up to 10 animals around Driest
Point, located 5 km (3.1 mi) north of the project location (L. Bethel,
personal communication, June 11, 2020 as cited in the application).
Therefore, NMFS authorizes that 2 groups of 5 harbor porpoises (average
group size of local sightings) per 5 days of in-water work may be taken
by Level B harassment. Expressed in another way, this is an average of
2 harbor porpoise per day of in-water work. Therefore, we estimate 52
exposures over the course of the project (26 days * 2 porpoises per day
= 52). No take by Level A harassment is authorized or anticipated to
occur, as the calculated isopleths for high-frequency cetaceans are 134
m or less during all activities except during DTH for 24-in piles of
limited duration where they are 198 m-412 m. The shutdown zones (Table
10) are larger for all calculated Level A harassment isopleths during
all pile driving activities (vibratory, impact and DTH) for all
cetaceans.
Harbor Seal
There are no density estimates of harbor seals available in the
project area. Harbor seals are commonly sighted in the waters of the
inside passages throughout Southeast Alaska. Surveys in 2015 estimated
429 (95 percent Confidence Interval [CI]: 102-1,203) harbor seals on
the northwest coast of Annettte Island, between Metlakatla and Walden
Point. An additional 90 (95 percent CI: 18-292) were observed along the
southwest coast of Annette Island, between Metlakatla and Tamgas Harbor
(NOAA 2019). The Alaska Fisheries Science Center identifies three
haulouts in Port Chester (less than a mile from the project area) and
three additional haulouts north of Driest Point (3.7 mi from the
project are). Abundance estimates for these haulouts are not available,
but they are all denoted as having had more than 50 harbor seals at one
point in time (NOAA 2020). However, local biologists report only small
numbers (fewer than 10) of harbor seals are regularly observed in Port
Chester. As many as 10 to 15 harbor seals may utilize Sylburn Harbor,
north of Metlakatla across Driest Point (R. Cook, personal
communication, June 5, 2020 as cited in the application), as a haulout
location. Therefore, NMFS authorizes 15 harbor seals may be taken by
Level B harassment each day, for a total of 390 exposures (26 days * 15
seals per day = 390). No take by Level A harassment is authorized or
anticipated to occur, as the calculated isopleths are 60 m or less
during all activities except during DTH for 24-in piles of limited
duration where they are 89-186 m. In addition, the shutdown zones
(Table 10) are larger for all calculated Level A harassment isopleths
during all pile driving activities (vibratory, impact and DTH) for all
pinnipeds.
Steller Sea Lion
There are no density estimates of Steller sea lions available in
the project area. Steller sea lions are common within the project area;
however, systematic counts or surveys have not been completed in the
area directly surrounding Metlakatla. Three haulouts are located within
150 km (93 mi) of the project area (Fritz et al. 2016a); the nearest
documented haulout is West Rock, about 45 km (28 mi) south of
Metlakatla. West Rock had a count of 703 individuals during a June 2017
survey and 1,101 individuals during a June 2019 survey (Sweeney et al.
2017, 2019). Aerial surveys occurred intermittently between 1994 and
2015, and averaged 982 adult Steller sea lions (Fritz et al., 2016b).
Anecdotal evidence indicate that 3 to 4 Steller sea lions utilize a
buoy as a haulout near the entrance of Port Chester, about 3.2 km (2
mi) from the project location (L. Bethel, personal communication, June
11, 2020 as cited in the application). Steller sea lions are not known
to congregate near the cannery in Metlakatla. Anecdotal evidence
suggests that the species assemblages and abundance in Metlakatla are
similar to Tongass Narrows where 20 sea lions are estimated each day
during July through September. A recent monitoring report for Tongass
Narrows reported 41 individual sightings of Steller sea lions with 9
takes by Level B harassment in May 2021. Therefore to be conservative,
NMFS authorizes two groups of 10 Steller sea lions (20 Steller sea
lions) may be taken by Level B harassment for a total of 520 Steller
sea lions (26 days * 20 sea lions per day = 520). No take by Level A
harassment is authorized or anticipated to occur as the largest Level A
isopleth calculated was 13.5 m during DTH of 24-in piles and the
remaining isopleths were less than 10 m. In addition, the shutdown
zones (Table 10) are larger for all calculated Level A harassment
isopleths during all pile driving activities (vibratory, impact and
DTH) for all pinnipeds.
Table 9 below summarizes the authorized take for all the species
described above as a percentage of stock abundance.
Table 9--Take Estimates as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Level B
Species Stock (nEST) harassment Percent of stock
----------------------------------------------------------------------------------------------------------------
Minke Whale............................. Alaska (N/A).............. 12 N/A.
Humpback Whale.......................... Central North Pacific 104 Less than 1 percent.
(10,103).
Killer Whale............................ Alaska Resident (2,347)... 15 0.6.a
Northern Resident (302)... 5.0.a
West Coast Transient (349) 4.3.a
Pacific White-Sided Dolphin............. North Pacific (26,880).... 92 Less than 1 percent.
Dall's Porpoise......................... Alaska (83,400) b......... 30 Less than 1 percent.
Harbor Porpoise......................... Southeast Alaska (NA)..... 52 NA.
Harbor Seal............................. Clarence Strait (27,659).. 390 1.4.
[[Page 43200]]
Steller Sea Lion........................ Eastern U.S. (43,201)..... 520 1.2.
----------------------------------------------------------------------------------------------------------------
a Take estimates are weighted based on calculated percentages of population for each distinct stock, assuming
animals present would follow same probability of presence in project area.
b Jefferson et al. 2019 presents the first abundance estimates for Dall's porpoise in the waters of Southeast
Alaska with highest abundance recorded in spring (N = 5,381, CV = 25.4 percent), lower numbers in summer (N =
2,680, CV = 19.6 percent), and lowest in fall (N = 1,637, CV = 23.3 percent). However, NMFS currently
recognizes a single stock of Dall's porpoise in Alaskan waters and an estimate of 83,400 Dall's porpoises is
used by NMFS for the entire stock (Muto et al., 2020).
Mitigation
In order to issue an IHA under Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned) the likelihood of effective implementation (probability
implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
General
The AKDOT&PF will follow mitigation procedures as outlined in their
Marine Mammal Monitoring Plan and as described below. In general, if
poor environmental conditions restrict visibility full visibility of
the shutdown zone, pile driving installation and removal as well as DTH
would be delayed.
Training
The AKDOT&PF must ensure that construction supervisors and crews,
the monitoring team, and relevant AKDOT&PF staff are trained prior to
the start of construction activity subject to this IHA, so that
responsibilities, communication procedures, monitoring protocols, and
operational procedures are clearly understood. New personnel joining
during the project must be trained prior to commencing work.
Avoiding Direct Physical Interaction
The AKDOT&PF must avoid direct physical interaction with marine
mammals during construction activity. If a marine mammal comes within
10 m of such activity, operations will cease and vessels will reduce
speed to the minimum level required to maintain steerage and safe
working conditions, as necessary to avoid direct physical interaction.
Shutdown Zones
For all pile driving/removal and DTH activities, the AKDOT&PF will
establish a shutdown zone for a marine mammal species that is greater
than its corresponding Level A harassment zone (Table 10). The purpose
of a shutdown zone is generally to define an area within which shutdown
of the activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). The shutdown
zones are larger than all the calculated Level A harassment isopleths
for all pile driving/removal and DTH activities for cetaceans and
pinnipeds.
Table 10--Pile Driving Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
Shutdown distance (meters)
Activity Pile diameter Pile type or number -------------------------------
of piles Cetaceans Pinnipeds
----------------------------------------------------------------------------------------------------------------
Vibratory Installation/Removal.... 16- and 24-in........ Battered and Plumb... 50 50
DTH............................... 24-in................ Temporary............ 200 200
Battered, Permanent.. 260 120
Plumb, Permanent..... 415 200
DTH............................... 8-in................. Permanent............ 100 50
Impact............................ 24-in................ 3 piles.............. 135 100
2 piles..............
1 pile............... 100
----------------------------------------------------------------------------------------------------------------
[[Page 43201]]
Soft Start
The AKDOT&PF must use soft start techniques when impact pile
driving. Soft start requires contractors to provide an initial set of
three strikes from the hammer at reduced energy, followed by a 30-
second waiting period. Then two subsequent reduced-energy strike sets
would occur. A soft start will be implemented at the start of each
day's impact pile driving and at any time following cessation of impact
pile driving for a period of 30 minutes or longer. Soft start is not
required during vibratory pile driving and removal activities.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the planned mitigation measures provide the means
of effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth, requirements pertaining to
the monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
action area. Effective reporting is critical both to compliance as well
as ensuring that the most value is obtained from the required
monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
[ssquf] Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
[ssquf] Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
[ssquf] Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
[ssquf] How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
[ssquf] Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
[ssquf] Mitigation and monitoring effectiveness.
Monitoring Zones
The AKDOT&PF will conduct monitoring to include the area within the
Level B harassment presented in Table 8. Monitoring will include all
areas where SPLs are equal to or exceed 120 dB rms (for vibratory pile
driving/removal and DTH) and 160 dB rms (for impact pile driving).
These zones provide utility for monitoring conducted for mitigation
purposes (i.e., shutdown zone monitoring) by establishing monitoring
protocols for areas adjacent to the shutdown zones. Monitoring of the
Level B harassment zones enables observers to be aware of and
communicate the presence of marine mammals in the project area, but
outside the shutdown zone, and thus prepare for potential shutdowns of
activity.
Pre-Start Clearance Monitoring
Pre-start clearance monitoring must be conducted during periods of
visibility sufficient for the lead PSO to determine the shutdown zones
clear of marine mammals. Pile driving and DTH may commence when the
determination is made.
Visual Monitoring
Monitoring must take place from 30 minutes (min) prior to
initiation of pile driving and DTH activity (i.e., pre-start clearance
monitoring) through 30 min post-completion of pile driving and DTH
activity. If a marine mammal is observed entering or within the
shutdown zones, pile driving and DTH activity will be delayed or
halted. If pile driving or DTH is delayed or halted due to the presence
of a marine mammal, the activity may not commence or resume until
either the animal has voluntarily exited and been visually confirmed
beyond the shutdown zone or 15 min have passed without re-detection of
the animal. Pile driving and DTH activity will be halted upon
observation of either a species for which incidental take is not
authorized or a species for which incidental take has been authorized
but the authorized number of takes has been met, entering or within the
harassment zone.
PSO Monitoring Requirements and Locations
The AKDOT&PF will establish monitoring locations as described in
the Marine Mammal Monitoring Plan. PSOs will be responsible for
monitoring, the shutdown zones, the Level B harassment zones, and the
pre-clearance zones, as well as effectively documenting Level B
harassment take. As described in more detail in the Reporting section
below, they will also (1) document the frequency at which marine
mammals are present in the project area, (2) document behavior and
group composition (3) record all construction activities, and (4)
document observed reactions (changes in behavior or movement) of marine
mammals during each sighting. Observers will monitor for marine mammals
during all in-water pile installation/removal and DTH associated with
the project. The AKDOT&PF will monitor the project area to the extent
possible based on the required number of PSOs, required monitoring
locations, and environmental conditions. Monitoring will be conducted
by PSOs from land. For all pile driving and DTH activities, a minimum
of one observer must be assigned to each active pile driving and DTH
location to monitor the shutdown zones. Two PSOs must be onsite during
all in-water activities and will monitor from the best vantage point.
Due to the remote nature of the area, the PSOs will meet with the
future designated Contractor and AKDOT&PF to determine the most
appropriate observation location(s) for monitoring during pile
installation and removal. These observers must record all observations
of marine mammals, regardless of distance from the pile being driven or
during DTH.
In addition, PSOs will work in shifts lasting no longer than 4 hrs
with at least a 1-hr break between shifts, and will not perform duties
as a PSO for more than 12 hrs in a 24[hyphen]hr period (to reduce PSO
fatigue).
Monitoring of pile driving will be conducted by qualified, NMFS-
approved PSOs. The AKDOT&PF shall adhere to the following conditions
when selecting PSOs:
[ssquf] PSOs must be independent (i.e., not construction personnel)
and have no other assigned tasks during monitoring periods;
[[Page 43202]]
[ssquf] At least one PSO must have prior experience performing the
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization;
[ssquf] Other PSOs may substitute other relevant experience,
education (degree in biological science or related field), or training;
[ssquf] Where a team of three PSOs are required, a lead observer or
monitoring coordinator shall be designated. The lead observer must have
prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued incidental take authorization; and
[ssquf] PSOs must be approved by NMFS prior to beginning any
activity subject to this IHA.
The AKDOT&PF will ensure that the PSOs have the following
additional qualifications:
[ssquf] Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
[ssquf] Experience and ability to conduct field observations and
collect data according to assigned protocols;
[ssquf] Experience or training in the field identification of
marine mammals, including the identification of behaviors;
[ssquf] Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
[ssquf] Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
[ssquf] Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Final Report
The AKDOT&PF will submit a draft report to NMFS on all monitoring
conducted under this IHA within 90 calendar days of the completion of
monitoring or 60 calendar days prior to the requested issuance of any
subsequent IHA for construction activity at the same location,
whichever comes first. A final report must be prepared and submitted
within 30 days following resolution of any NMFS comments on the draft
report. If no comments are received from NMFS within 30 days of receipt
of the draft report, the report shall be considered final. All draft
and final marine mammal monitoring reports must be submitted to
<a href="/cdn-cgi/l/email-protection#f4a4a6dabda0a4dab99b9a9d809b869d9a93a691849b868087b49a9b9595da939b82"><span class="__cf_email__" data-cfemail="e2b2b0ccabb6b2ccaf8d8c8b968d908b8c85b087928d909691a28c8d8383cc858d94">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#9cd5c8ccb2d9fbfbf9eedcf2f3fdfdb2fbf3ea"><span class="__cf_email__" data-cfemail="28617c78066d4f4f4d5a6846474949064f475e">[email protected]</span></a>. The report
must contain the informational elements described in the Marine Mammal
Monitoring Plan and, at minimum, must include:
[ssquf] Dates and times (begin and end) of all marine mammal
monitoring;
[ssquf] Construction activities occurring during each daily
observation period, including:
[cir] How many and what type of piles were driven and by what
method (e.g., impact, vibratory, DTH);
[cir] Total duration of driving time for each pile (vibratory
driving) and number of strikes for each pile (impact driving); and
[cir] For DTH, duration of operation for both impulsive and non-
pulse components.
[ssquf] PSO locations during marine mammal monitoring;
[ssquf] Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
[ssquf] Upon observation of a marine mammal, the following
information:
[cir] PSO who sighted the animal and PSO location and activity at
time of sighting;
[cir] Time of sighting;
[cir] Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
[cir] Distance and bearing of each marine mammal observed to the
pile being driven for each sighting (if pile driving and DTH was
occurring at time of sighting);
[cir] Estimated number of animals (min/max/best);
[cir] Estimated number of animals by cohort (adults, juveniles,
neonates, group composition etc.;
[cir] Animal's closest point of approach and estimated time spent
within the harassment zone; and
[cir] Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses to the activity (e.g., no response
or changes in behavioral state such as ceasing feeding, changing
direction, flushing, or breaching).
[ssquf] Detailed information about implementation of any mitigation
(e.g., shutdowns and delays), a description of specific actions that
ensued, and resulting changes in behavior of the animal, if any; and
[ssquf] All PSO datasheets and/or raw sightings data.
Reporting of Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the AKDOT&PF must report the
incident to NMFS Office of Protected Resources (OPR)
(<a href="/cdn-cgi/l/email-protection#e4b4b6caadb0b4caa98b8a8d908b968d8a83b681948b969097a48a8b8585ca838b92"><span class="__cf_email__" data-cfemail="29797b07607d7907644647405d465b40474e7b4c59465b5d5a6947464848074e465f">[email protected]</span></a>), NMFS (301-427-8401) and to the
Alaska regional stranding network (877-925-7773) as soon as feasible.
If the death or injury was clearly caused by the specified activity,
the AKDOT&PF must immediately cease the specified activities until NMFS
OPR is able to review the circumstances of the incident and determine
what, if any, additional measures are appropriate to ensure compliance
with the terms of this IHA. The AKDOT&PF will not resume their
activities until notified by NMFS. The report must include the
following information:
[ssquf] Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[ssquf] Species identification (if known) or description of the
animal(s) involved;
[ssquf] Condition of the animal(s) (including carcass condition if
the animal is dead);
[ssquf] Observed behaviors of the animal(s), if alive;
[ssquf] If available, photographs or video footage of the
animal(s); and
[ssquf] General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken''
[[Page 43203]]
through harassment, NMFS considers other factors, such as the likely
nature of any responses (e.g., intensity, duration), the context of any
responses (e.g., critical reproductive time or location, migration), as
well as effects on habitat, and the likely effectiveness of the
mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
As stated in the mitigation section, shutdown zones that are larger
than the Level A harassment zones will be implemented, which, in
combination with the fact that the zones are small to begin with, is
expected to avoid the likelihood of Level A harassment for marine
mammals species.
Exposures to elevated sound levels produced during pile driving
activities may cause behavioral disturbance of some individuals, but
they are expected to be mild and temporary. Effects on individuals that
are taken by Level B harassment, as enumerated in the Take Estimation
section, on the basis of reports in the literature as well as
monitoring from other similar activities, will likely be limited to
reactions such as increased swimming speeds, increased surfacing time,
or decreased foraging (if such activity were occurring) (e.g., Thorson
and Reyff, 2006; Lerma, 2014). Most likely, individuals will simply
move away from the sound source and be temporarily displaced from the
areas of pile driving, although even this reaction has been observed
primarily only in association with impact pile driving. These reactions
and behavioral changes are expected to subside quickly when the
exposures cease.
During all impact driving, implementation of soft start procedures
and monitoring of established shutdown zones will be required,
significantly reducing the possibility of injury. Given sufficient
notice through use of soft start (for impact driving), marine mammals
are expected to move away from an irritating sound source prior to it
becoming potentially injurious. In addition, PSOs will be stationed
within the action area whenever pile driving/removal and DTH activities
are underway. Depending on the activity, the AKDOT&PF will employ the
use of two PSOs to ensure all monitoring and shutdown zones are
properly observed.
The project would likely not permanently impact any marine mammal
habitat since the project will occur within the same footprint as
existing marine infrastructure. The nearshore and intertidal habitat
where the project will occur is an area of relatively high marine
vessel traffic and some local individuals would likely be somewhat
habituated to the level of activity in the area, further reducing the
likelihood of more severe impacts. The closest pinniped haulouts are
used by harbor seals and are less than a mile from the project area;
however, for the reasons described immediately above (including the
nature of expected responses and the duration of the project) impacts
to reproduction or survival of individuals is not anticipated, much
less effects on the species or stock. There are no other biologically
important areas for marine mammals near the project area.
In addition, impacts to marine mammal prey species are expected to
be minor and temporary. Overall, the area impacted by the project is
very small compared to the available habitat around Metlakatla. The
most likely impact to prey will be temporary behavioral avoidance of
the immediate area. During pile driving/removal and DTH activities, it
is expected that fish and marine mammals would temporarily move to
nearby locations and return to the area following cessation of in-water
construction activities. Therefore, indirect effects on marine mammal
prey during the construction are not expected to be substantial.
In summary and as described above, the following factors primarily
support our determination that the impacts resulting from this activity
are not expected to adversely affect the species or stock through
effects on annual rates of recruitment or survival:
[ssquf] No mortality is anticipated or authorized;
[ssquf] No take by Level A harassment is expected or authorized;
[ssquf] Anticipated incidents of Level B harassment consist of, at
worst, temporary modifications in behavior;
[ssquf] The required mitigation measures (i.e., shutdown zones) are
expected to be effective in reducing the effects of the specified
activity;
[ssquf] Minimal impacts to marine mammal habitat/prey are expected;
[ssquf] The action area is located and within an active marine
commercial area, and;
[ssquf] There are no known biologically important areas in the
vicinity of the project, with the exception of nearby harbor seal
haulouts--however, as described above, exposure to the work conducted
in the vicinity of the haulouts is not expected to impact the
reproduction or survival of any individual seals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the planned
activity will have a negligible impact on all affected marine mammal
species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(A) and (D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. When the predicted number of individuals to
be taken is fewer than one third of the species or stock abundance, the
take is considered to be of small numbers. Additionally, other
qualitative factors may be considered in the analysis, such as the
temporal or spatial scale of the activities.
Take of six of the marine mammal stocks authorized will comprise at
most approximately 1.4 percent or less of the stock abundance. There
are no official stock abundances for harbor porpoise and minke whales;
however, as discussed in greater detail in the Description of Marine
Mammals in the Area of Specified Activities in the Federal Register
notice of the proposed IHA (86 FR 34203; June 29, 2021), we believe for
the abundance information that is available, the estimated takes are
likely small percentages of the stock abundance. For harbor porpoise,
the abundance for the Southeast Alaska stock is likely more represented
by the aerial surveys that were conducted as these surveys had better
coverage and were corrected for observer bias. Based on this data, the
estimated take could potentially be approximately 4 percent of the
stock abundance. However, this is unlikely and the percentage of the
stock taken is likely lower as the take
[[Page 43204]]
estimates are conservative and the project occurs in a small footprint
compared to the available habitat in Southeast Alaska. For minke
whales, in the northern part of their range they are believed to be
migratory and so few minke whales have been seen during three offshore
Gulf of Alaska surveys that a population estimate could not be
determined. With only twelve authorized takes for this species, the
percentage of take in relation to the stock abundance is likely to be
very small.
Based on the analysis contained herein of the planned activity
(including the mitigation and monitoring measures) and the anticipated
take of marine mammals, NMFS finds that small numbers of marine mammals
will be taken relative to the population size of the affected species
or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 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.
The project area does not spatially overlap any known subsistence
hunting. The project area is a developed area with regular marine
vessel traffic. Nonetheless, the AKDOT&PF provided advanced public
notice of construction activities to reduce construction impacts on
local residents, adjacent businesses, and other users of Port Chester
and nearby areas. This included notification to nearby Alaska Native
tribes that may have members who hunt marine mammals for subsistence.
Currently, the Metlakatla Indian Community does not authorize the
harvest of marine mammals for subsistence use (R. Cook, personal
communication, June 5, 2020 as cited in the application).
The planned project is not likely to adversely impact the
availability of any marine mammal species or stocks that are commonly
used for subsistence purposes or to impact subsistence harvest of
marine mammals in the region because construction activities are
localized and temporary and mitigation measures will be implemented to
minimize disturbance of marine mammals in the project area.
Accordingly, NMFS has determined that there will not be an unmitigable
adverse impact on the availability of any marine mammals for taking for
subsistence uses from the AKDOT&PF's planned activities.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the Alaska Regional
Office (AKRO).
NMFS is authorizing take of the Central North Pacific stock of
humpback whales, including individuals from the Mexico DPS of humpback
whales, which are listed under the ESA. The Permit and Conservation
Division completed a Section 7 consultation with the AKRO for the
issuance of this IHA. The AKRO's biological opinion states that the
action is not likely to jeopardize the continued existence of the
Mexico DPS of humpback whales.
Authorization
As a result of these determinations, NMFS authorizes an IHA to the
AKDOT&PF for conducting for the planned pile driving and removal
activities as well as DTH during construction of the Metlakatla
Seaplane Facility Refurbishment Project, Metlakatla, Alaska for one
year, beginning August 2021, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
Dated: August 3, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2021-16861 Filed 8-5-21; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on August 6, 2021.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.