Notice2021-12551
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Relocation of the Port of Alaska's South Floating Dock, Anchorage, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
June 15, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the Port of Alaska (POA) for authorization to take marine mammals incidental to pile driving associated with the relocation of the POA's South Floating Dock (SFD) in Knik Arm, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorizations and agency responses will be summarized in the final notice of our decision.
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[Federal Register Volume 86, Number 113 (Tuesday, June 15, 2021)]
[Notices]
[Pages 31870-31901]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-12551]
[[Page 31869]]
Vol. 86
Tuesday,
No. 113
June 15, 2021
Part III
Department of Commerce
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National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to the Relocation of the Port of Alaska's
South Floating Dock, Anchorage, Alaska; Notice
Federal Register / Vol. 86 , No. 113 / Tuesday, June 15, 2021 /
Notices
[[Page 31870]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XA660]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Relocation of the Port of
Alaska's South Floating Dock, Anchorage, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible Renewal.
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SUMMARY: NMFS has received a request from the Port of Alaska (POA) for
authorization to take marine mammals incidental to pile driving
associated with the relocation of the POA's South Floating Dock (SFD)
in Knik Arm, Alaska. Pursuant to the Marine Mammal Protection Act
(MMPA), NMFS is requesting comments on its proposal to issue an
incidental harassment authorization (IHA) to incidentally take marine
mammals during the specified activities. NMFS is also requesting
comments on a possible one-time, one-year renewal that could be issued
under certain circumstances and if all requirements are met, as
described in Request for Public Comments at the end of this notice.
NMFS will consider public comments prior to making any final decision
on the issuance of the requested MMPA authorizations and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than July 15,
2021.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Written comments should be submitted
via email to <a href="/cdn-cgi/l/email-protection#9ad3cecab4eee3e9f5f4b4f7f5f5e8ffdaf4f5fbfbb4fdf5ec"><span class="__cf_email__" data-cfemail="e8a1bcb8c69c919b8786c68587879a8da886878989c68f879e">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at
<a href="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Reny Tyson Moore, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the 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 the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
Accordingly, NMFS is preparing an Environmental Assessment (EA) to
consider the environmental impacts associated with the issuance of the
proposed IHA. NMFS' EA will be made available at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. We will review all comments submitted in
response to this notice prior to concluding our NEPA process or making
a final decision on the IHA request.
Summary of Request
On October 2, 2020, NMFS received a request from the POA for an IHA
to take marine mammals incidental to pile driving associated with the
relocation of the SFD in Knik Arm, Alaska. Revised applications were
submitted by POA on December 15, 2020, January 29, 2021, February 5,
2021, and March 5, 2021 that addressed comments provided by NMFS. The
application was deemed adequate and complete on March 17, 2021.
Additional revised applications were submitted on March 26, 2021 and
May 14, 2021. The POA's request is for take of a small number of six
species of marine mammals by Level B harassment and Level A harassment.
Neither the POA nor NMFS expects serious injury or mortality to result
from this activity and, therefore, an IHA is appropriate.
NMFS previously issued IHAs to the POA for pile driving (73 FR
41318, July 18, 2008; 74 FR 35136, July 20, 2009; 81 FR 15048, March
21, 2016; and 85 FR 19294, April 06, 2020). The POA has complied with
the requirements (e.g., mitigation, monitoring, and reporting) of all
previous IHAs and information regarding their monitoring results may be
found in the Effects of the Specified Activity on Marine Mammals and
their Habitat and Estimated Take sections.
Description of Proposed Activity
Overview
The POA is modernizing its marine terminals through the Port of
Alaska Modernization Program (PAMP). One of the first priorities of the
PAMP is to replace the existing Petroleum Oil Lubricants Terminal with
a new Petroleum Cement Terminal (PCT). Phase 1 of the PCT project is
complete, but for Phase 2 of the project to advance, the existing SFD,
a small multipurpose floating dock constructed in 2004, must be
relocated south of the PCT near the southern portion of the South
Backlands Stabilization project. The existing location of SFD will not
allow docking
[[Page 31871]]
operations at SFD once the PCT is constructed due to the close
proximity of one of the PCT mooring dolphins (a structure for berthing
and mooring of vessels). Therefore, it must be relocated.
Relocation of the SFD will include the removal of the existing
structure, including the access trestle and gangway, and installation
of twelve permanent 36-inch steel pipe piles: Ten vertical and two
battered. Construction of the SFD will also require the installation
and vibratory removal of up to six 24- or 36-inch template piles. All
pile installation will take place from a floating work barge and crane
with a vibratory hammer to the greatest extent possible. An impact
hammer may be used if a pile encounters refusal and cannot be advanced
to the necessary tip elevation with the vibratory hammer. An unconfined
bubble curtain system will be used to reduce in-water noise levels for
the installation of the sixteen vertical piles and removal of the six
temporary piles but will not be used during installation of the two
battered piles due to the angle of these piles.
Dates and Duration
The POA has requested that the IHA be valid for one year upon
issuance. In-water pile installation and removal associated with SFD
removal and construction is anticipated to take place on up to 24
nonconsecutive days between the date of issuance and November 2021.
Installation of permanent and temporary piles is anticipated to take 45
minutes per pile with 1-3 piles being installed per day over 7-18 days.
Removal of six temporary piles is anticipated to take 75 minutes per
pile with 1-3 piles being removed per day over 2-6 days. All pile-
driving will occur during daylight hours.
Specific Geographic Region
Cook Inlet is a large tidal estuary that exchanges waters at its
mouth with the Gulf of Alaska. The inlet is roughly 20,000 square
kilometers (km\2\; 7,700 square miles (mi\2\)) in area, with
approximately 1,350 linear km (840 mi) of coastline (Rugh et al., 2000)
and an average depth of approximately 100 meters (m) (330 feet (ft)).
Cook Inlet is generally divided into upper and lower regions by the
East and West Forelands. Freshwater input to Cook Inlet comes from
snowmelt and rivers, many of which are glacially fed and carry high
sediment loads. Currents throughout Cook Inlet are strong and tidally
periodic, with average velocities ranging from three to six knots
(Sharma and Burrell, 1970). Extensive tidal mudflats occur throughout
Cook Inlet, especially in the upper reaches, and are exposed at low
tides.
Cook Inlet is a seismically active region susceptible to
earthquakes and has some of the highest tides in North America (NOAA,
2015) that drive surface circulation. Tides in Cook Inlet are
semidiurnal, with two unequal high and low tides per tidal day (tidal
day = 24 hours, 50 minutes). Due to Knik Arm's predominantly shallow
depths and narrow widths, tides near Anchorage are greater than those
in the main body of Cook Inlet. The tides at the POA have a mean range
of about 8.0 m (26 ft), and the maximum water level has been measured
at more than 12.5 m (41 ft) at the Anchorage station (NOAA, 2015).
Maximum current speeds in Knik Arm, observed during spring ebb tide,
exceed 7 knots (12 feet/second). These tides result in strong currents
in alternating directions through Knik Arm and a well-mixed water
column. Cook Inlet contains substantial quantities of mineral
resources, including coal, oil, and natural gas. During winter, sea,
beach, and river ice are dominant physical forces within Cook Inlet. In
upper Cook Inlet, sea ice generally forms in October to November and
continues to develop through February or March (Moore et al., 2000).
Northern Cook Inlet bifurcates into Knik Arm to the north and
Turnagain Arm to the east. The POA is located in the southeastern
shoreline of Knik Arm in Anchorage, Alaska (Latitude 61[deg]15' N,
Longitude 149[deg]52' W; Seward Meridian) (Figure 1). Knik Arm is
generally considered to begin at Point Woronzof, 7.4 km (4.6 mi)
southwest of the POA. From Point Woronzof, Knik Arm extends about 48 km
(30 mi) in a north-northeasterly direction to the mouths of the
Matanuska and Knik rivers. At Cairn Point, just northeast of the POA,
Knik Arm narrows to about 2.4 km (1.5 mi) before widening to as much as
8 km (5 mi) at the tidal flats northwest of Eagle Bay at the mouth of
Eagle River, which are heavily utilized by Cook Inlet Beluga Whales
(CIBWs). Approximately 60 percent of Knik Arm is exposed at mean lower
low water (MLLW). The intertidal (tidally influenced) areas of Knik
Arm, including those at the POA, are mudflats, both vegetated and
unvegetated, which consist primarily of fine, silt-sized glacial flour.
The POA's boundaries currently occupy an area of approximately 129
acres. Other commercial and industrial activities related to secure
maritime operations are located near the POA on Alaska Railroad
Corporation (ARRC) property immediately south of the POA, on
approximately 111 acres. The PCT footprint spans approximately 0.87
acre and is approximately 0.74 km (0.46 m) north of Ship Creek, a
location of concentrated marine mammal activity during seasonal runs of
several salmon species. Ship Creek flows into Knik Arm through the
Municipality of Anchorage industrial area. The perpendicular distance
to the west bank directly across Knik Arm from the POA is approximately
4.2 km (2.6 mi).
BILLING CODE 3510-22-P
[[Page 31872]]
[GRAPHIC] [TIFF OMITTED] TN15JN21.013
BILLING CODE 3510-22-C
Detailed Description of Specific Activity
Located within the Municipality of Anchorage on Knik Arm in upper
Cook Inlet, the POA (Figure 1) provides critical infrastructure for the
citizens of Anchorage and a majority of the citizens of Alaska. The
POA's existing infrastructure and support facilities were constructed
largely in the 1960s. Port facilities are substantially past their
design life, have degraded to levels of
[[Page 31873]]
marginal safety, and are in many cases functionally obsolete,
especially in regard to seismic design criteria and condition. To
address these deficiencies, the POA is modernizing its marine terminals
through the PAMP. Plans for modernization include replacing
deteriorated pile-supported infrastructure with new pile-supported
infrastructure. One of the first priorities of the PAMP is to replace
the existing Petroleum Oil Lubricants Terminal with a new structure
that exceeds current seismic standards. For the new PCT Project to
advance, the existing SFD, a small multipurpose floating dock
constructed in 2004, must be relocated south of the PCT near the
southern portion of the South Backlands Stabilization project (Figure
1). The existing location of SFD will not allow docking operations at
SFD once the PCT is constructed due to close proximity of one of the
PCT mooring dolphins.
The purpose of the SFD is to provide staging, mooring, and docking
of small vessels, such as first responder (e.g., Anchorage Fire
Department, U.S. Coast Guard) rescue craft, small work skiffs, and
occasionally tug boats, in an area close to the daily operations at the
Port. Upper Cook Inlet near Anchorage exhibits the largest tide range
in the United States and one of the largest tide ranges in the world,
with an average daily difference between high and low tide of 26.2 feet
and an extreme difference of up to 41 feet (NOAA, 2015). The ability of
first responders to conduct response operations during low tide stages
requires access to the SFD, as the waterline is inaccessible for
vessels at the Anchorage public boat launch at Ship Creek during low
tide stages. The planned relocation of the SFD south of the new PCT
structure will provide continuous access to the water, and relocation
is needed to continue to provide timely, safe access for rescue
personnel and vessels in the northern portion of Cook Inlet.
Relocation of the SFD will include the removal of the existing
structure, including the float and gangway, and installation of twelve
permanent 36-inch steel piles: Four for the gangway and eight for the
floating dock (Table 1). Ten of the permanent piles will be plumb
(i.e., vertical) piles; but two of these piles, located at the south
corner of the floating dock, will be battered piles due to lateral ice
flow conditions. Two of the permanent 36-inch gangway piles at Bent B,
the bent closest to shore, may be installed when the area is de-
watered, but will likely be installed in water. Temporary template
piles may be required to assist with permanent pile placement and would
consist of up to six 24- or 36-inch steel pipe piles (Table 1): 4 For
the gangway and 2 for the float. To allow for flexibility in design,
temporary piles may be all of one size or a combination of 24- and 36-
inch steel pipe piles. The piles from the existing SFD piles will be
left in place and will not be removed.
All piles will be installed with a vibratory hammer to the greatest
extent possible, with each pile requiring approximately 45 minutes to
install (Table 1), based on an analysis of PCT Phase 1 data. An impact
hammer may be required if a pile encounters refusal and cannot be
advanced to the necessary tip elevation with the vibratory hammer.
Refusal criteria for a vibratory hammer is defined by the hammer
manufacturer and is described as the pile not advancing one foot within
30 seconds of vibratory hammer operation at full speed. Three piles
have deeper embedment depth than others and may reach refusal before
the specified minimum tip elevation. In such a situation, an impact
hammer would be needed to drive these piles to their required depth. A
small number of total piles, estimated up to five piles, may reach
refusal before the tip elevation is reached, requiring up to 20 minutes
of impact installation each at one pile per day. POA estimates that
each of these piles could require up to 1,000 strikes, which was the
mean number of strikes measured for 48-inch production piles during the
PCT Phase 1 construction sound source verification (SSV) study (Reyff
et al., 2021). It is likely that the number of strikes will be less due
to the smaller pile sizes associated with SFD. To be conservative,
1,000 strikes were used to calculate Level A harassment zone sizes. It
is assumed that if a pile does require impact installation, the
vibratory installation time would be reduced by a commensurate amount
(i.e., 15 minutes of impact installation would replace 15 minutes of
vibratory installation), and the overall duration of installation would
remain the same.
Temporary template piles (n = 6) will be removed with a vibratory
hammer (Table 1). Based on an analysis of PCT Phase 1 data, each
temporary pile will require approximately 75 minutes of vibratory
hammer removal. Knik Arm soils have demonstrated a strong set up and
resistance condition on temporary piles due to dense clay composition,
making removal lengthier and more difficult than installation. The
temporary piles for the SFD will be in place for only approximately
three weeks and will not be load-bearing, in contrast to the piles used
for the PCT temporary trestle that were in place for approximately five
months and subject to loads from the construction crane. The temporary
SFD piles will likely require less time for removal than PCT piles at
approximately two-thirds duration. Based on this, the estimated removal
time is approximately two-thirds of the duration required for vibratory
removal of 36-inch temporary trestle piles during PCT Phase 1
construction. All of the existing SFD float and gangway piles will
remain in place; a vibratory hammer will not be required for their
removal.
Table 1--Pile Details and Estimated Effort Required for Pile Installation and Removal
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Potential Production rate (piles/day)
impact -----------------------------
Vibratory strikes per
Number of Number of installation Vibratory removal pile, if Days of Days of
Pipe pile diameter Feature plumb piles battered duration per pile duration per pile needed (up installation removal
piles (minutes) (minutes) to 5 piles; Installation Removal
one pile
per day)
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36-inch......................... Floating Dock...... 6 2 45................. n/a................ 1,000 1-3 n/a 4-12 n/a
Gangway............ 4 0 n/a................ 1,000 1-3 n/a n/a
24- or 36-inch.................. Temporary Template 6 0 45................. 75................. 1,000 1-2 1-3 3-6 2-6
Piles.
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Project Totals 16 2 13.5 hours......... 7.5 hours.......... ........... .............. ........... 7-18 2-6
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[[Page 31874]]
The POA will use an unconfined bubble curtain noise attenuation
system to mitigate noise propagation during vibratory installation and
potential impact installation of the ten permanent plumb piles and six
temporary plumb piles and vibratory removal of the six temporary piles
when water depth is deep enough to deploy a bubble curtain
(approximately 3 m). Pile installation or removal in the dry, which is
a completely de-watered state, is unlikely but, if it occurs, will be
conducted without a bubble curtain. A bubble curtain will not be used
with the two battered piles due to the angle of installation. Use of an
unconfined bubble curtain is proposed instead of a confined bubble
curtain in order to reduce the need for additional template piles that
would be required to stabilize a confined bubble curtain.
All pile installation will take place from a floating work barge
and crane. A marine-based operation is required because of the extreme
tidal range, which precludes use of a land-based crane in the absence
of a temporary support trestle. The floating work barge will require
sufficient water depth for support. Opportunities to install piles when
the project site is dewatered will be limited. Piles will be installed
in water and multiple piles will likely not be driven concurrently.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
There are six species of marine mammals that may be found in upper
Cook Inlet during the proposed pile driving activities. Sections 3 and
4 of the POA's 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-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>), and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS's website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>). Additional information on CIBWs
may be found in NMFS' 2016 Recovery Plan for the CIBW (Delphinapterus
leucas), available online at <a href="https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas">https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas</a>.
Table 2 lists all species or stocks for which take is expected and
proposed to be 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 (2019). PBR is defined by the MMPA as the maximum number of
animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population (as described in NMFS's SARs). While no
mortality is anticipated or authorized here, PBR and annual serious
injury and mortality from anthropogenic sources are included here as
gross indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' 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. 2019 SARs (e.g., Muto et al., 2020a) and 2020 draft SARs
(Muto et al., 2020b). All values presented in Table 2 are the most
recent available at the time of publication and are available in the
2019 SARs (Muto et al., 2020a) and 2020 draft SARs (Muto et al., 2020b)
(available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
Table 2--Marine Mammal Species Potentially Occurring in Upper Cook Inlet, Alaska
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Western North Pacific.. E/D; Y 1,107 (0.3, 865, 2006) 3 2.8
Central North Pacific.. -/-; Y 10,103 (0.3, 7890, 83 26
2006).
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............. E/D; Y 279 (0.06, 267, 2018). 0.53 0
Killer whale.................... Orcinus orca........... Alaska Resident........ -/-; N 2,347 (N/A, 1102,347, 24 1
2012).
Alaska Transient....... -/-; N 587 (N/A, 587, 2012).. 5.87 0.8
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena............... Gulf of Alaska......... -/-; Y 31,046 (0.214, N/A, Undet 72
1998).
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Steller sea lion................ Eumetopias jubatus..... Western................ E/D; Y 53,932 (N/A, 52,932 318 255
2013).
Family Phocidae (earless seals):
[[Page 31875]]
Harbor seal..................... Phoca vitulina......... Cook Inlet/Shelikof.... -/-; N 28,411 (N/A, 26,907, 807 107
2018).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="http://www.nmfs.noaa.gov/pr/sars/">www.nmfs.noaa.gov/pr/sars/</a>. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance. In some cases, CV is not applicable because it has not been calculated.
\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.
As indicated above, all six species (with six managed stocks) in
Table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur, and we have proposed
authorizing it. Marine mammals occurring in Cook Inlet that are not
expected to be observed in the project area and for which take is not
proposed include gray whales (Eschrichtius robustus), minke whales
(Balaenoptera acutorostrata), and Dall's porpoise (Phocoenoides dalli).
Data from the Alaska Marine Mammal Stranding Network database (NMFS,
unpublished data) provide additional support for the determination that
these species rarely occur in upper Cook Inlet. Since 2011, only one
minke whale and one Dall's porpoise have been documented as stranded in
the portion of Cook Inlet north of Point Possession. Both were dead
upon discovery; it is unknown if they were alive upon their entry into
upper Cook Inlet or drifted into the area with the tides. No gray
whales were reported as stranded in upper Cook Inlet during this time
period; however, one juvenile gray whale was observed on May 24, 2020
during PCT Phase 1 construction monitoring (61 North Environmental,
2021). This whale was first observed mid-inlet off Port MacKenzie then
travelled along the southeastern shore of Knik Arm until it was last
sighted near Point Woronzof. On May 27, 2020, there were reports that a
juvenile gray whale, believed to be the same whale, was stranded in the
Twentymile River, at the eastern end of Turnagain Arm, approximately 50
mi southeast of Knik Arm. The animal remained in the river for a week,
before swimming out of the river. The whale later stranded and died
about 25 mi away at the mouth of the Theodore River on June 12, 2020.
No in water pile installation occurred on 23 to 25 May, and there is no
indication that work at the PCT had any effect on the animal. Based on
photos and video NMFS collected of the whale, veterinarians determined
the whale was in fair to poor condition (see <a href="https://www.fisheries.noaa.gov/feature-story/alaska-gray-whale-ume-update-twentymile-river-whale-likely-one-twelve-dead-gray-whales">https://www.fisheries.noaa.gov/feature-story/alaska-gray-whale-ume-update-twentymile-river-whale-likely-one-twelve-dead-gray-whales</a> for more
information). With very few exceptions, minke whales, gray whales, and
Dall's porpoises do not occur in upper Cook Inlet; and, therefore, take
of these species is not requested in this application.
In addition, sea otters (Enhydra lutris) may be found in Cook
Inlet. However, sea otters are managed by the U.S. Fish and Wildlife
Service (USFWS) and are not considered further in this document.
Humpback Whale
Currently, three stocks of humpback whales are recognized in the
North Pacific, migrating between their respective summer/fall feeding
areas and winter/spring calving and mating areas (Baker et al., 1998;
Calambokidis et al., 1997): (1) The California/Oregon/Washington and
Mexico stock, (2) the Central North Pacific stock, and (3) the Western
North Pacific stock. Humpback whales from the Western North Pacific
breeding stock overlap broadly on summer feeding grounds with whales
from the Central North Pacific breeding stock, as well as with whales
that winter in the Revillagigedo Islands in Mexico (Muto et al., 2020a,
2020b). Despite this overlap, the whales seasonally found in Cook Inlet
are probably of the Central North Pacific stock (Muto et al., 2020a,
2020b). The Central North Pacific stock winters in Hawaii (Baker et
al., 1986) and summers from British Columbia to the Aleutian Islands
(Calambokidis et al., 1997), including Cook Inlet.
The humpback whale ESA listing final rule (81 FR 62259, September
8, 2016) delineated 14 Distinct Population Segments (DPSs) with
different listing statuses. The most comprehensive photo-identification
data available suggest that approximately 89 percent of all humpback
whales in the Gulf of Alaska are members of the Hawaii DPS, 11 percent
are from the Mexico DPS, and less than 1 percent are from the western
North Pacific DPS (Wade et al., 2016). The Hawaii DPS is not listed
under the ESA, the Mexico DPS is listed as threatened, and the Western
North Pacific DPS is listed as endangered under the ESA. Members of
different DPSs are known to intermix in feeding grounds; therefore, all
waters off the coast of Alaska should be considered to have ESA-listed
humpback whales. NMFS is in the process of reviewing humpback whale
stock structure under the MMPA in light of the 14 DPSs established
under the ESA.
Humpback whales are encountered regularly in lower Cook Inlet and
occasionally in mid-Cook Inlet; however, sightings are rare in upper
Cook Inlet (e.g., Witteveen et al., 2011). There have been few
sightings of humpback whales near the project area. Humpback whales
were not documented during POA construction or scientific monitoring
from 2005 to 2011 or during 2016 (Cornick and Pinney, 2011; Cornick and
Saxon-Kendall, 2008, 2009; Cornick and Seagars, 2016; Cornick et al.,
2010, 2011; ICRC, 2009, 2010a, 2011a, 2012; Markowitz and McGuire,
2007; Prevel-Ramos et al., 2006). Observers monitoring the Ship Creek
Small Boat Launch from August 23 to September 11, 2017, recorded two
sightings, each of a single humpback whale, which was presumed to be
the same individual. One other humpback whale sighting has been
recorded for the immediate vicinity of the project area. This event
involved a stranded whale that was sighted near a number of locations
in upper Cook Inlet before washing ashore at Kincaid Park in 2017; it
is unclear as to whether the humpback whale was alive or deceased upon
entering Cook Inlet waters. No humpbacks were observed from April-
November 2020 during Phase 1 PCT construction
[[Page 31876]]
monitoring (61 North Environmental, 2021).
The Central North Pacific stock is the focus of a large whale-
watching industry in its wintering grounds (Hawaii) and summering
grounds (Alaska). The growth of the whale-watching industry is an
ongoing concern as preferred habitats may be abandoned if disturbance
levels are too high (Muto et al., 2020a, 2020b). Other potential
impacts include elevated levels of sound from anthropogenic sources
(e.g., shipping, military sonars), harmful algal blooms (Geraci et al.,
1989), possible changes in prey distribution with climate change,
entanglement in fishing gear, ship strikes due to increased vessel
traffic (e.g., from increased shipping in higher latitudes and through
the Bering Sea with changes in sea-ice coverage), and oil and gas
activities. An intentional unauthorized take of a humpback whale by
Alaska Natives in Toksook Bay was documented in 2016 (Muto et al.,
2020a, 2020b); however, no subsistence use of humpback whales occurs in
Cook Inlet.
Humpback whale populations were considerably reduced as a result of
intensive commercial exploitation during the 20th century. Currently,
the overall trend for most humpback whale populations found in U. S.
waters is positive and points toward recovery (81 FR 62259; September
8, 2016); however, this may not be uniform for all breeding areas. A
sharp decline in observed reproduction and encounter rates of humpback
whales from the Central North Pacific stock between 2013 and 2018 has
been related to oceanographic anomalies and consequent impacts on prey
resources (Cartwright et al., 2019), suggesting that humpback whales
are vulnerable to major environmental changes.
Beluga Whale
The CIBW stock is a small, geographically isolated population
separated from other beluga whale populations by the Alaska Peninsula.
The population is genetically distinct from other Alaska populations,
suggesting the peninsula is an effective barrier to genetic exchange
(O'Corry-Crowe et al., 1997). The CIBW population is estimated to have
declined from 1,300 animals in the 1970s (Calkins, 1989) to about 340
animals in 2014 (Shelden et al., 2015), and to 279 animals in 2018
(Wade et al., 2019). The precipitous decline documented in the mid-
1990s was attributed to unsustainable subsistence practices by Alaska
Native hunters (harvest of >50 whales per year) (Mahoney and Shelden,
2000). Harvesting of CIBWs has not occurred since 2008 (NMFS, 2008).
Despite protection from hunting and other threats, this stock has
not rebounded and continues to decline (Wade et al., 2019, Muto et al.,
2020b). The population was declining at the end of the period of
unregulated harvest, with the relatively steep decline ending in 1999,
coincident with harvest removals dropping from an estimated 42 in 1998
to just 0 to 2 whales per year in 2000 to 2006 (and with no removals
after 2006). From 1999 to 2016, the rate of decline of the population
was estimated to be 0.4 percent (SE = 0.6 percent) per year, with a 73
percent probability of a population decline. This rate increased from
2006 to 2016 to 0.5 percent per year, (with a 70 percent probability of
a population decline) (Shelden et al., 2017). The latest estimates
suggest that this rate has further increased to 2.3 percent decline per
year from 2008 to 2018, with a 99.7 percent probability of population
decline in the future (Wade et al., 2019, Muto et al., 2020b). No
human-caused mortality or serious injury of CIBWs has been recently
documented.
The current best abundance estimate of the CIBW population from the
aerial survey data is 279 (95 percent probability interval 250 to 317).
This is based on the estimate of smoothed abundance for 2018, as
described in Sheldon and Wade (2019). A comparison of the population
estimates over time is presented in Figure 2. While Sheldon and Wade
(2019) provides explanations for the differences between model results,
including inadequacies and biases, the authors do not postulate on the
reason for population decline in general (which was evident using both
models); however, recent literature suggests prey reductions may be a
critical contributing factor (Norman et al., 2019). This is not
unexpected as reduced prey availability has been directly linked to
increased mortality and reduced health and survival of other marine
mammals populations such as the Southern Resident killer whale (e.g.,
Ward et al., 2009, Wasser et al., 2017) and California sea lion (e.g.,
McClatchie et al., 2016). The CIBW stock was designated as depleted
under the MMPA in 2000 (65 FR 34590; May 21, 2000) and listed as
endangered under the ESA in 2008 (73 FR 62919; October 22, 2008).
Therefore, the CIBW stock is considered a strategic stock.
[[Page 31877]]
[GRAPHIC] [TIFF OMITTED] TN15JN21.014
Mortality related to live stranding events, where a CIBW group
strands as the tide recedes, has been regularly observed in upper Cook
Inlet. Most whales involved in a live stranding event survive, although
some associated deaths may not be observed if the whales die later from
live-stranding-related injuries (Vos and Shelden, 2005, Burek-
Huntington et al., 2015). Between 2014 and 2018, there were reports of
approximately 79 CIBWs involved in three known live stranding events,
plus one suspected live stranding event with two associated deaths
reported (NMFS, 2016a; NMFS, unpubl. Data, Muto et al., 2020b). In
2014, necropsy results from two whales found in Turnagain Arm suggested
that a live stranding event contributed to their deaths as both had
aspirated mud and water. No live stranding events were reported prior
to the discovery of these dead whales, suggesting that not all live
stranding events are observed. A CIBW calf that stranded alive in 2017
was sent to the Alaska SeaLife Center for rehabilitation and then
transferred to SeaWorld in San Antonio, Texas, in 2018. Most live
strandings occur in Knik Arm and Turnagain Arm, which are shallow and
have large tidal ranges, strong currents, and extensive mudflats.
Another source of CIBW mortality in Cook Inlet is predation by
transient-type (mammal-eating) killer whales (NMFS, 2016a; Sheldon et
al., 2003).
In its Recovery Plan (NMFS, 2016a), NMFS identified several threats
to CIBWs. Potential threats include: (1) High concern: Catastrophic
events (e.g., natural disasters, spills, mass strandings), cumulative
effects of multiple stressors, and noise; (2) medium concern: Disease
agents (e.g., pathogens, parasites, and harmful algal blooms), habitat
loss or degradation, reduction in prey, and unauthorized take; and (3)
low concern: Pollution, predation, and subsistence harvest. The
recovery plan did not treat climate change as a distinct threat but
rather as a consideration in the threats of high and medium concern.
Other potential threats most likely to result in direct human-caused
mortality or serious injury of this stock include ship strikes.
The CIBW stock remains within Cook Inlet throughout the year,
showing only small seasonal shifts in distribution (Goetz et al.,
2012a, Lammers et al., 2013, Castallotte et al., 2015; Shelden et al.,
2015a, 2018; Lowery et al., 2019). NMFS designated two areas,
consisting of 7,809 km\2\ (3,016 mi\2\) of marine and estuarine
environments, considered essential for the species' survival and
recovery as critical habitat (76 FR 20180; April 11, 2011). However, in
recent years the range of the CIBW whale has contracted to the upper
reaches of Cook Inlet because of the decline in the population (Rugh et
al., 2010), and almost the entire population can be found in northern
Cook Inlet from late spring through the summer and into the fall (Muto
et al., 2020b). Area 1 of the CIBW critical habitat encompasses all
marine waters of Cook Inlet north of a line connecting Point Possession
(61.04[deg] N, 150.37[deg] W) and the mouth of Three Mile Creek
(61.08.55[deg] N, 151.04.40[deg] W), including waters of the Susitna,
Little Susitna, and Chickaloon Rivers below mean higher high water.
This area provides important habitat during ice-free months and is used
intensively by CIBWs between April and November (NMFS, 2016a). The POA,
the adjacent navigation channel, and the turning basin were excluded
from critical habitat designation due to national
[[Page 31878]]
security reasons (76 FR 20180; April 11, 2011). More information on
CIBW critical habitat can be found at <a href="https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale">https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale</a>.
Aerial surveys were conducted by NMFS each year during from 1994 to
2012 (Rugh et al., 2000, 2005; Shelden et al., 2013, 2019) to document
distribution and abundance of CIBWs. NMFS changed to a biennial survey
schedule starting in 2014 after analysis showed there would be little
reduction in the ability to detect a trend given the current growth
rate of the population (Hobbs, 2013). The collective survey results
show that CIBWs have been consistently found near or in river mouths
along the northern shores of upper Cook Inlet (i.e., north of East and
West Foreland). In particular, CIBW groups are seen in the Susitna
River Delta, Knik Arm, and along the shores of Chickaloon Bay. Small
groups have also been recorded farther south in Kachemak Bay, Redoubt
Bay (Big River), and Trading Bay (McArthur River) prior to 1996 but
very rarely thereafter. Since the mid-1990s, most (96 to 100 percent)
CIBWs in upper Cook Inlet have been concentrated in shallow areas near
river mouths (Sheldon et al., 2015), no longer occurring in the central
or southern portions of Cook Inlet (Hobbs et al., 2008). Based on these
aerial surveys, the concentration of CIBWs in the northernmost portion
of Cook Inlet appears to be consistent from June to October (Rugh et
al., 2000, 2004a, 2004b, 2005, 2006, 2007). Research reports generated
from the surveys can be found at <a href="https://www.fisheries.noaa.gov/alaska/endangered-species-conservation/research-reports-and-publications-cook-inlet-beluga-whales">https://www.fisheries.noaa.gov/alaska/endangered-species-conservation/research-reports-and-publications-cook-inlet-beluga-whales</a>.
Though CIBWs can be found throughout the inlet at any time of year,
they spend the ice-free months generally in the upper Cook Inlet,
shifting into the middle and lower Inlet in winter (Hobbs et al.,
2005). In 1999, one CIBW was tagged with a satellite transmitter, and
its movements were recorded from June through September of that year.
Since 1999, 18 CIBWs in upper Cook Inlet have been captured and fitted
with satellite tags to provide information on their movements during
late summer, fall, winter, and spring (Goetz et al., 2012a; Shelden et
al., 2015a, 2018). All tagged CIBWs remained in Cook Inlet (Shelden et
al., 2015a, 2018). Most tagged whales were in the lower to middle inlet
(70 to 100 percent of tagged whales) during January through March, near
the Susitna River Delta from April to July (60 to 90 percent of tagged
whales) and in the Knik and Turnagain Arms from August to December
(Ezer et al., 2013). More recently, the Marine Mammal Lab has conducted
long-term passive acoustic monitoring demonstrating seasonal shifts in
CIBW concentrations throughout Cook Inlet. Castellote et al. (2015)
conducted long-term acoustic monitoring at 13 locations throughout Cook
Inlet between 2008 and 2015: North Eagle Bay, Eagle River Mouth, South
Eagle Bay, Six Mile, Point MacKenzie, Cairn Point, Fire Island, Little
Susitna, Beluga River, Trading Bay, Kenai River, Tuxedni Bay, and Homer
Spit; the former six stations being located within Knik Arm. In
general, the observed seasonal distribution is in accordance with
descriptions based on aerial surveys and satellite telemetry: CIBW
detections are higher in the upper inlet during summer, peaking at
Little Susitna, Beluga River, and Eagle Bay, followed by fewer
detections at those locations during winter. Higher detections in
winter at Trading Bay, Kenai River, and Tuxedni Bay suggest a broader
CIBW distribution in the lower inlet during winter.
CIBWs are generally concentrated near the warmer waters of river
mouths during the spring and summer because that is where prey
availability is high and predator occurrence is low (Moore et al.,
2000). Goetz et al. (2012b) modeled habitat preferences using NMFS'
1994-2008 June abundance survey data. In large areas, such as the
Susitna Delta (Beluga to Little Susitna Rivers) and Knik Arm, there was
a high probability that CIBWs were in larger group sizes. CIBW presence
also increased closer to rivers with Chinook salmon (Oncorhynchus
tshawytscha) runs, such as the Susitna River. Movement has been
correlated with the peak discharge of seven major rivers emptying into
Cook Inlet. Boat-based surveys from 2005 to the present (McGuire and
Stephens, 2017) and results from passive acoustic monitoring across the
entire inlet (Castellote et al., 2015) also support seasonal patterns
observed with other methods. Based on long-term passive acoustic
monitoring, seasonally, foraging behavior was more prevalent during
summer, particularly at upper inlet rivers, than during winter.
Foraging index was highest at Little Susitna, with a peak in July-
August and a secondary peak in May, followed by Beluga River and then
Eagle Bay; monthly variation in the foraging index indicates CIBWs
shift their foraging behavior among these three locations from April
through September.
CIBWs in Cook Inlet are believed to mostly calve between mid-May
and mid-July, and concurrently breed between late spring and early
summer (NMFS, 2016a), primarily in upper Cook Inlet. The only known
observed occurrence of calving occurred on July 20, 2015, in the
Susitna Delta area (T. McGuire, pers. comm. March 27, 2017). The first
neonates encountered during each field season from 2005 through 2015
were always seen in the Susitna River Delta in July. The photographic
identification team's documentation of the dates of the first neonate
of each year indicate that calving begins in mid-late July/early
August, generally coinciding with the observed timing of annual maximum
group size. Probable mating behavior of CIBWs was observed in April and
May of 2014, in Trading Bay. Young CIBWs are nursed for two years and
may continue to associate with their mothers for a considerable time
thereafter (Colbeck et al., 2013).
The POA conducted dedicated monitoring during PCT Phase 1
construction between April and November 2020 (61 North Environmental,
2021). In total, protected species observers (PSOs) observed 245 groups
of approximately 987 CIBWs near the POA (group sizes ranged from 1 to
53 individuals), with the most number of individuals and groups being
seen in August (N = 56 groups of 274 individuals) and September (N = 73
groups of 276 individuals). CIBWs were observed in every month of the
project (except during October, which only included three project and
monitoring days) with the highest sightings per unit effort, measured
as CIBWs per hour of observation, occurring at the end of August and
beginning of September.
Killer Whale
Killer whales are found throughout the North Pacific Ocean. Along
the west coast of North America, seasonal and year-round occurrence of
killer whales occur has been noted along the entire Alaska coast
(Braham and Dahlheim, 1982), in British Columbia and Washington inland
waterways (Bigg et al., 1990), and along the outer coasts of
Washington, Oregon, and California (Green et al., 1992; Barlow 1995,
1997; Forney et al., 1995). Killer whales from these areas have been
labeled as ``resident,'' ``transient,'' and ``offshore'' type killer
whales (Bigg et al., 1990, Ford et al., 2000, Dahlheim et al., 2008)
based on aspects of morphology, ecology, genetics, and behavior (Ford
and Fisher, 1982; Baird and Stacey, 1988; Baird et al., 1992; Hoelzel
et al., 1998, 2002; Barrett Lennard, 2000; Dahlheim et al., 2008). Two
stocks of killer whales may be present in upper Cook Inlet: The Eastern
North Pacific Alaska Resident stock and the Gulf of Alaska, Aleutian
Islands, and Bering Sea
[[Page 31879]]
Transient stock. Both ecotypes overlap in the same geographic area;
however, they maintain social and reproductive isolation and feed on
different prey species.
While there have been some anecdotal reports of killer whales
feeding on CIBWs in upper Cook Inlet, sightings in this region and near
the POA are rare (e.g., NMFS, 2016a; Sheldon et al., 2003). During
aerial surveys conducted between 1993 and 2004 in Cook Inlet, killer
whales were only observed on three flights, and all sightings were
located in the Kachemak and English Bay area, south of the POA (Rugh et
al., 2005). Acoustic monitoring carried out by Castellote et al. (2016)
between 2008 and 2013 only detected one transient killer whale at
Beluga River, located along the western shore of Cook Inlet, west of
the POA. Surveys conducted by Funk et al., (2005), Ireland et al.,
(2005), Brueggeman et al., (2007, 2008a, 2008b), and McGuire et al.,
(2020) did not observe killer whales in the vicinity of or north of the
POA. Lastly, killer whales were not observed during POA construction or
scientific monitoring from 2005 to 2011, during the 2016 Test Pile
Program (TPP), or during Phase 1 of the PCT project carried out between
April-November 2020 (61 North Environmental, 2021). Therefore, very few
killer whales, if any, are expected to approach or be near the project
area during construction of the SFD.
Killer whales are not harvested for subsistence in Alaska.
Potential threats most likely to result in direct human-caused
mortality or serious injury of killer whales in this region include oil
spills, vessel strikes, and interactions with fisheries. Based on
currently available data, a minimum estimate of the mean annual
mortality and serious injury rate for both the Alaska Residents and
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stocks due
to U.S. commercial fisheries is less than 10 percent of the PBR and,
therefore, is considered to be insignificant and approaching zero
mortality and serious injury rate. Therefore, neither stock is
classified as a strategic stock (Muto et al., 2020b).
Harbor Porpoise
Harbor porpoises primarily frequent the coastal waters of the Gulf
of Alaska and Southeast Alaska (Dahlheim et al., 2000, 2009), typically
occurring in waters less than 100 m deep (Hobbs and Waite, 2010).
Harbor porpoise prefer nearshore areas, bays, tidal areas, and river
mouths (Dahlheim et al., 2000, 2009, 2015; Hobbs and Waite, 2010). In
Alaskan waters, NMFS has designated three stocks of harbor porpoises
for management purposes: Southeast Alaska, Gulf of Alaska, and Bering
Sea Stocks (Muto et al., 2020b). Porpoises found in Cook Inlet belong
to the Gulf of Alaska Stock, which is distributed from Cape Suckling to
Unimak Pass.
Although harbor porpoises have been frequently observed during
aerial surveys in Cook Inlet (Shelden et al., 2014), most sightings are
of single animals and are concentrated at Chinitna and Tuxedni bays on
the west side of lower Cook Inlet (Rugh et al., 2005). The occurrence
of larger numbers of porpoise in the lower Cook Inlet may be driven by
greater availability of preferred prey and possibly less competition
with CIBWs, as CIBWs move into upper inlet waters to forage on Pacific
salmon during the summer months (Shelden et al., 2014).
There has been an increase in harbor porpoise sightings in upper
Cook Inlet over the past two decades (Shelden et al., 2014). Small
numbers of harbor porpoises have been consistently reported in upper
Cook Inlet between April and October (Prevel-Ramos et al., 2008).
Harbor porpoises have been observed within Knik Arm during monitoring
efforts since 2005. During POA construction from 2005 through 2011 and
in 2016, harbor porpoises were reported in 2009, 2010, and 2011
(Cornick and Saxon-Kendall, 2008, 2009; Cornick and Seagars, 2016;
Cornick et al., 2010, 2011; Markowitz and McGuire, 2007; Prevel-Ramos
et al., 2006). In 2009, 20 harbor porpoises were observed during
construction monitoring, with sightings in June, July, August, October,
and November. Harbor porpoises were observed twice in 2010, once in
July and again in August. In 2011, POA monitoring efforts documented
harbor porpoises five times, with a total of six individuals, in
August, October, and November at the POA (Cornick et al., 2011). During
other monitoring efforts conducted in Knik Arm, there were four
sightings of harbor porpoises in 2005 (Shelden et al., 2014), and a
single harbor porpoise was observed within the vicinity of the POA in
October 2007. More recent monitoring conducted during Phase 1 PCT
construction documented 15 groups (18 individuals) of harbor porpoises
near the POA between April and November 2020 (group sizes ranged 1-2
individuals) (61 North Environmental, 2021).
Estimates of human-caused mortality and serious injury from
stranding data and fisherman self-reports are underestimates because
not all animals strand or are self-reported nor are all stranded
animals found, reported, or have the cause of death determined. In
addition, the trend of this stock is unknown given existing data is
more than eight years old. NMFS considers this stock strategic because
the level of mortality and serious injury would likely exceed the PBR
level if we had accurate information on stock structure, a newer
abundance estimate, and complete fisheries observer coverage. Given
their shallow water distribution, harbor porpoise are vulnerable to
physical modifications of nearshore habitats resulting from urban and
industrial development (including waste management and nonpoint source
runoff) and activities such as construction of docks and other over-
water structures, filling of shallow areas, dredging, and noise
(Linnenschmidt et al., 2013). Subsistence users have not reported any
harvest from the Gulf of Alaska harbor porpoise stock since the early
1900s (Shelden et al., 2014).
Steller Sea Lion
Steller sea lions inhabiting Cook Inlet belong to the Western
distinct population segment (WDPS), and this is the stock considered in
this analysis. NMFS defines the Steller sea lion WDPS as all
populations west of longitude 144[deg] W to the western end of the
Aleutian Islands. The most recent comprehensive aerial photographic and
land-based surveys of WDPS Steller sea lions in Alaska were conducted
during the 2018 (Aleutian Islands west of Shumagin Islands) and 2019
(Southeast Alaska and Gulf of Alaska east of Shumagin Islands) breeding
seasons (Sweeney et al., 2018, 2019). The WDPS of Steller sea lions is
currently listed as endangered under the ESA (55 FR 49204, November 26,
1990) and designated as depleted under the MMPA. NMFS designated
critical habitat on August 27, 1993 (58 FR 45269). The critical habitat
designation for the WDPS of Steller sea lions was determined to include
a 37 km (20 nm) buffer around all major haul-outs and rookeries, and
associated terrestrial, atmospheric, and aquatic zones, plus three
large offshore foraging areas, none of which occurs in the project
area. Steller sea lions feed largely on walleye pollock, salmon, and
arrowtooth flounder during the summer, and walleye pollock and Pacific
cod during the winter (Sinclair and Zeppelin, 2002). Except for salmon,
none of these are found in abundance in upper Cook Inlet (Nemeth et
al., 2007).
Within Cook Inlet, Steller sea lions primarily inhabit lower Cook
Inlet. However, they occasionally venture to upper Cook Inlet and Knik
Arm and may be attracted to salmon runs in the region. Steller sea
lions have been
[[Page 31880]]
observed near the POA in 2009 (ICRC 2009), 2016 (Cornick and Seagars,
2016), and in 2020 during Phase 1 PCT construction monitoring (61 North
Environmental, 2021). During POA construction monitoring in June of
2009, a Steller sea lion was documented three times (within the same
day) in Knik Arm and was believed to be the same individual (ICRC,
2009). In 2016, Steller sea lions were observed on two separate days.
On May 2, 2016, one individual was sighted. On May 25, 2016, there were
five Steller sea lion sightings within a 50-minute period, and these
sightings occurred in areas relatively close to one another suggesting
they were likely the same animal (Cornick and Seagars, 2016). Most
recently, up to six Steller sea lions were sighted across four days
between May 29 and June 24, 2020 during Phase PCT 1 construction
monitoring (61 North Environmental, 2021). At least two of these
sightings may have been re-sights on the same individual. An additional
seven unidentified pinnipeds were observed that could have been Steller
sea lions or harbor seals (61 North Environmental, 2021).
The minimum estimated mean annual level of human-caused mortality
and serious injury for Western U.S. Steller sea lions between 2014 and
2018 is 255 sea lions: 38 in U.S. commercial fisheries, 0.8 in unknown
(commercial, recreational, or subsistence) fisheries, 3.2 in marine
debris, 3.6 due to other causes (arrow strike, entangled in hatchery
net, illegal shooting, mortality incidental to Marine Mammal Protection
Act (MMPA) authorized research), and 209 in the Alaska Native
subsistence harvest (Muto et al., 2020b). However, there are multiple
nearshore commercial fisheries which are not observed; thus, there is
likely to be unreported fishery-related mortality and serious injury of
Steller sea lions.
Several factors may have been important drivers of the decline of
the stock. However, there is uncertainty about threats currently
impeding their recovery, particularly in the Aleutian Islands. Many
factors have been suggested as causes of the steep decline in abundance
of western Steller sea lions observed in the 1980s, including
competitive effects of fishing, environmental change, disease,
contaminants, killer whale predation, incidental take, and illegal and
legal shooting (Atkinson et al., 2008; NMFS, 2008a). A number of
management actions have been implemented since 1990 to promote the
recovery of the Western U.S. stock of Steller sea lions, including 3-
nmi no-entry zones around rookeries, prohibition of shooting at or near
sea lions, and regulation of fisheries for sea lion prey species (e.g.,
walleye pollock, Pacific cod, and Atka mackerel) (Sinclair et al.,
2013, Tollit et al., 2017). Additionally, potentially deleterious
events, such as harmful algal blooms (Lefebvre et al., 2016) and
disease transmission across the Arctic (VanWormer et al., 2019) that
have been associated with warming waters, could lead to potentially
negative population-level impacts on Steller sea lions.
Harbor Seal
Harbor seals inhabit coastal and estuarine waters off Baja
California, north along the western coasts of the United States,
British Columbia, and Southeast Alaska, west through the Gulf of Alaska
and Aleutian Islands, and in the Bering Sea north to Cape Newenham and
the Pribilof Islands. They haul out on rocks, reefs, beaches, and
drifting glacial ice and feed in marine, estuarine, and occasionally
fresh waters. Harbor seals generally are non-migratory, with local
movements associated with such factors as tides, weather, season, food
availability, and reproduction (Scheffer and Slipp, 1944; Fisher, 1952;
Bigg, 1969, 1981; Hastings et al., 2004). NMFS currently identifies
twelve stocks of harbor seals based largely on genetic structure (Muto
et al., 2020a). Harbor seals from the Cook Inlet/Shelikof Strait stock,
which ranges from the southwest tip of Unimak Island east along the
southern coast of the Alaska Peninsula to Elizabeth Island off the
southwest tip of the Kenai Peninsula, including Cook Inlet, Knik Arm,
and Turnagain Arm, are considered in this analysis.
Harbor seals belonging to this stock inhabit the coastal and
estuarine waters of Cook Inlet and are observed in both upper and lower
Cook Inlet throughout most of the year (Boveng et al., 2012; Shelden et
al., 2013). Research on satellite-tagged harbor seals conducted between
2004 and 2006 observed several movement patterns within Cook Inlet
(Boveng et al., 2012), including a strong seasonal pattern of more
coastal and restricted spatial use during the spring and summer
(breeding, pupping, molting) and more wide-ranging movements within and
outside of Cook Inlet during the winter months, with some seals ranging
as far as Shumigan Islands. During summer months, movements and
distribution was mostly confined to the west side of Cook Inlet and
Kachemak Bay, and seals captured in lower Cook Inlet generally
exhibited site fidelity by remaining south of the Forelands in lower
Cook Inlet after release (Boveng et al., 2012).
The presence of harbor seals in upper Cook Inlet is seasonal.
Harbor seals are commonly observed along the Susitna River and other
tributaries within upper Cook Inlet during eulachon and salmon
migrations (NMFS, 2003). The major haulout sites for harbor seals are
located in lower Cook Inlet with fewer sites in upper Cook Inlet
(Montgomery et al., 2007). In the project area (Knik Arm), harbor seals
tend to congregate near the mouth of Ship Creek (Cornick et al., 2011;
Shelden et al., 2013), likely foraging on salmon and eulachon runs.
Approximately 138 harbor seals were observed during POA monitoring
prior to 2020, with sightings ranging from three individuals in 2008 to
59 individuals in 2011. During 2020 PCT Phase 1 construction
monitoring, harbor seals were regularly observed in the vicinity of the
POA with frequent observations near the mouth of Ship Creek, located
approximately 700 m southeast of the SFD location. From 27 April
through 24 November 2020, a total of 340 individual harbor seals were
observed (61 North Environmental, 2021). An additional seven
unidentified pinnipeds were observed that could have been Steller sea
lions or harbor seals. Harbor seals were observed almost daily during
construction, with 54 individuals documented in July, 66 documented in
August, and 44 sighted in September (61North Environmental, 2021).
The most current population trend estimate of the Cook Inlet/
Shelikof Strait stock is approximately -111 seals per year, with a
probability that the stock is decreasing of 0.609 (Muto et al., 2020a).
The estimated level of human-caused mortality and serious injury for
this stock is 234 seals, of which 233 seals are taken for subsistence
uses. Between 2013 and 2017, there were two reports of Cook Inlet/
Shelikof Strait harbor seal mortality and serious injury due to
entanglements in fishing gear, including one in a Cook Inlet salmon set
gillnet in 2014 and one in an unidentified net in 2017, resulting in a
mean annual mortality and serious injury rate of 0.4 harbor seals from
this stock due to interactions with unknown (commercial, recreational,
or subsistence) fisheries (Muto et al., 2020a). Additional potential
threats most likely to result in direct human-caused mortality or
serious injury for all stocks of harbor seals in Alaska include
unmonitored subsistence harvests, incidental takes in commercial
fisheries, illegal shooting, and entanglements in marine debris (Delean
et al., 2020, Muto et al., 2020a). Disturbance by cruise vessels is an
additional threat for harbor seal stocks that occur in glacial fjords
(Jansen et al., 2010, 2015; Matthews et
[[Page 31881]]
al., 2016). The average annual harvest of this stock of harbor seals
between 2004 and 2008 was 233 seals per year. The annual harvest in
2014 was 104 seals (Muto et al., 2020a). This stock is not designated
as depleted under the MMPA or listed as threatened or endangered under
the ESA, and the minimum estimate of the mean annual level of human-
caused mortality and serious injury does not exceed PBR; therefore, the
Cook Inlet/Shelikof Strait stock of harbor seals is not classified as a
strategic stock (Muto et al., 2020a).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al., (2007) recommended that marine mammals be
divided into functional hearing groups based on directly measured or
estimated hearing ranges on the basis of available behavioral response
data, audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al., (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al., 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Six marine mammal species (four cetacean and two pinniped (one otariid
and one phocid) species) have the reasonable potential to co-occur with
the proposed construction activities. Please refer to Table 2. Of the
cetacean species that may be present, one is classified as low-
frequency cetaceans (i.e., all mysticete species), two are classified
as mid-frequency cetaceans (i.e., all delphinid and ziphiid species and
the sperm whale), and one is classified as high-frequency cetaceans
(i.e., harbor porpoise and Kogia spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Sound Sources
The primary relevant stressor to marine mammals from the proposed
activity is the introduction of noise into the aquatic environment;
therefore, we focus our impact analysis on the effects of anthropogenic
noise on marine mammals. To better understand the potential impacts of
exposure to pile driving noise, we describe sound source
characteristics below. Specifically, we look at the following two ways
to characterize sound: by its temporal (i.e., continuous or
intermittent) and its pulse (i.e., impulsive or non-impulsive)
properties. Continuous sounds are those whose sound pressure level
remains above that of the ambient sound, with negligibly small
fluctuations in level (NIOSH, 1998; ANSI, 2005), while intermittent
sounds are defined as sounds with interrupted levels of low or no sound
(NIOSH, 1998). Impulsive sounds, such as those generated by impact pile
driving, are typically transient, brief (<1 sec), broadband, and
consist of a high peak pressure with rapid rise time and rapid decay
(ANSI, 1986; NIOSH, 1998). The majority of energy in pile impact pulses
is at frequencies below 500 hertz (Hz). Impulsive sounds, by
definition, are intermittent. Non-impulsive sounds, such as those
generated by vibratory pile driving, can be broadband, narrowband or
tonal, brief or prolonged, and typically do not have a high peak sound
pressure with rapid rise/decay time that impulsive sounds do (ANSI,
1995; NIOSH, 1998). Non-impulsive sounds can be intermittent or
continuous. Similar to impact pile driving, vibratory pile driving
generates low frequency sounds. Vibratory pile driving is considered a
non-impulsive, continuous source. Discussion on the appropriate
harassment threshold associated with these types of sources
[[Page 31882]]
based on these characteristics can be found in the Estimated Take
section.
Potential Effects of Pile Driving--In general, the effects of
sounds from pile driving to marine mammals might result in one or more
of the following: Temporary or permanent hearing impairment, non-
auditory physical or physiological effects, behavioral disturbance, and
masking (Richardson et al., 1995; Nowacek et al., 2007; Southall et
al., 2007). The potential for and magnitude of these effects are
dependent on several factors, including receiver characteristics (e.g.,
age, size, depth of the marine mammal receiving the sound during
exposure); the energy needed to drive the pile (usually related to pile
size, depth driven, and substrate), the standoff distance between the
pile and receiver; and the sound propagation properties of the
environment.
Impacts to marine mammals from pile driving activities are expected
to result primarily from acoustic pathways. As such, the degree of
effect is intrinsically related to the received level and duration of
the sound exposure, which are in turn influenced by the distance
between the animal and the source. The further away from the source,
the less intense the exposure should be. The type of pile driving also
influences the type of impacts, for example, exposure to impact pile
driving may result in temporary or permanent hearing impairment, while
auditory impacts are unlikely to result from exposure to vibratory pile
driving. The substrate and depth of the habitat affect the sound
propagation properties of the environment. Shallow environments are
typically more structurally complex, which leads to rapid sound
attenuation. In addition, substrates that are soft (e.g., sand) absorb
or attenuate the sound more readily than hard substrates (e.g., rock)
which may reflect the acoustic wave. Soft porous substrates also likely
require less time to drive the pile, and possibly less forceful
equipment, which ultimately decrease the intensity of the acoustic
source.
Richardson et al., (1995) described zones of increasing intensity
of effect that might be expected to occur, in relation to distance from
a source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects (i.e., permanent hearing
impairment, certain non-auditory physical or physiological effects)
only briefly as we do not expect that there is a reasonable likelihood
that POA's activities would result in such effects (see below for
further discussion).
NMFS defines a noise-induced threshold shift (TS) as ``a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level'' (NMFS, 2016b). The amount of
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007).
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS
(2018), there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing and vocalization frequency range of the
exposed species relative to the signal's frequency spectrum (i.e., how
animal uses sound within the frequency band of the signal; e.g.,
Kastelein et al., 2014), and the overlap between the animal and the
source (e.g., spatial, temporal, and spectral). When analyzing the
auditory effects of noise exposure, it is often helpful to broadly
categorize sound as either impulsive--noise with high peak sound
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. When considering auditory effects, vibratory pile
driving is considered a non-impulsive source while impact pile driving
is treated as an impulsive source.
Permanent Threshold Shift--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB
threshold shift approximates PTS onset (see NMFS 2018 for review).
Temporary Threshold Shift--NMFS defines TTS as a temporary,
reversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Based on data from
cetacean TTS measurements (see Finneran 2015 for a review), a TTS of 6
dB is considered the minimum threshold shift clearly larger than any
day-to-day or session-to-session variation in a subject's normal
hearing ability (Schlundt et al., 2000; Finneran et al., 2000; Finneran
et al., 2002).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Schlundt et al. (2000) performed a study exposing five bottlenose
dolphins and two beluga whales (same individuals as Finneran's studies)
to intense one second tones at different frequencies. The resulting
levels of fatiguing stimuli necessary to induce 6 dB or larger masked
TTSs were generally between 192 and 201 dB re: 1 microPascal ([mu]Pa).
Dolphins began to exhibit altered behavior at levels of 178-193 dB re:
1[mu]Pa and above; beluga whales displayed altered behavior at 180-196
dB re: 1 [mu]Pa and above. At the conclusion of the study, all
thresholds were at baseline values.
There are a limited number of studies investigating the potential
for cetacean TTS from pile driving and only one has elicited a small
amount of TTS in a single harbor porpoise individual (Kastelein et al.,
2015). However,
[[Page 31883]]
captive bottlenose dolphins and beluga whales have exhibited changes in
behavior when exposed to pulsed sounds (Finneran et al., 2000, 2002,
2005). The animals tolerated high received levels of sound before
exhibiting aversive behaviors. Experiments on a beluga whale showed
that exposure to a single watergun impulse at a received level of 207
kiloPascal (kPa) (30 psi) p-p, which is equivalent to 228 dB p-p,
resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz,
respectively. Thresholds returned to within 2 dB of the pre-exposure
level within four minutes of the exposure (Finneran et al., 2002).
Although the source level of pile driving from one hammer strike is
expected to be lower than the single watergun impulse cited here,
animals being exposed for a prolonged period to repeated hammer strikes
could receive more sound exposure in terms of SEL than from the single
watergun impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the
aforementioned experiment (Finneran et al., 2002). Results of these
studies suggest odontocetes are susceptible to TTS from pile driving,
but that they seem to recover quickly from at least small amounts of
TTS.
Behavioral Responses--Behavioral disturbance may include a variety
of effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Disturbance may result in changing durations
of surfacing and dives, number of blows per surfacing, or moving
direction and/or speed; reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or
feeding); visible startle response or aggressive behavior (such as
tail/fluke slapping or jaw clapping); avoidance of areas where sound
sources are located. Pinnipeds may increase their haul-out time,
possibly to avoid in-water disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-specific
and any reactions depend on numerous intrinsic and extrinsic factors
(e.g., species, state of maturity, experience, current activity,
reproductive state, auditory sensitivity, time of day), as well as the
interplay between factors (e.g., Richardson et al., 1995; Wartzok et
al., 2003; Southall et al., 2007; Weilgart, 2007; Archer et al., 2010).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see Appendices
B-C of Southall et al. (2007) for a review of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that
[[Page 31884]]
respiration rates may either be unaffected or could increase, depending
on the species and signal characteristics, again highlighting the
importance in understanding species differences in the tolerance of
underwater noise when determining the potential for impacts resulting
from anthropogenic sound exposure (e.g., Kastelein et al., 2001, 2005b,
2006; Gailey et al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
(Eubalaena glacialis) have been observed to shift the frequency content
of their calls upward while reducing the rate of calling in areas of
increased anthropogenic noise (Parks et al., 2007). In some cases,
animals may cease sound production during production of aversive
signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
(Eschrictius robustus) are known to change direction--deflecting from
customary migratory paths--in order to avoid noise from seismic surveys
(Malme et al., 1984). Avoidance may be short-term, with animals
returning to the area once the noise has ceased (e.g., Bowles et al.,
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey
et al., 2007). Longer-term displacement is possible, however, which may
lead to changes in abundance or distribution patterns of the affected
species in the affected region if habituation to the presence of the
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al.,
2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil 1997; Fritz et al, 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b, Wright et al., 2007) and, more rarely, studied in
wild populations (e.g.,
[[Page 31885]]
Romano et al., 2002a). For example, Rolland et al., (2012) found that
noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
Specific to CIBWs, we have several years of marine mammal
monitoring data demonstrating the behavioral responses to pile driving
at the POA. Previous pile driving activities range from the
installation and removal of sheet pile driving to installation of 48-in
pipe piles with both vibratory and impact hammers, and vibratory
installation of 72-inch air bubble casings. Kendall and Cornick (2015)
provide a comprehensive overview of four years of scientific marine
mammal monitoring conducted during the POA's Expansion Project. These
were observations made independent of pile driving activities (i.e.,
not construction based PSOs). The authors investigated CIBWs behavior
before and during pile driving activity at the POA. Sighting rates,
mean sighting duration, behavior, mean group size, group composition,
and group formation were compared between the two periods. A total of
about 2,329 h of sampling effort was completed across 349 d from 2005
to 2009. Overall, 687 whales in 177 groups were documented during the
69 days that whales were sighted. A total of 353 and 1,663 hours of
pile driving took place in 2008 and 2009, respectively. There was no
relationship between monthly CIBW sighting rates and monthly pile
driving rates (r = 0.19, p = 0.37). Sighting rates before (n = 12; 0.06
<plus-minus> 0.01) and during (n = 13; 0.01 <plus-minus> 0.03) pile
driving were not significantly different. However, sighting duration of
CIBWs decreased significantly during pile driving (39 <plus-minus> 6
min before and 18 <plus-minus> 3 min during). There were also
significant differences in behavior before versus during pile driving.
CIBWs primarily traveled through the study area both before and during
pile driving; however, traveling increased relative to other behaviors
during pile driving. Suspected feeding decreased during pile driving
although the sample size was low as feeding was observed on only two
occasions before pile driving and on zero occasions during pile
driving. Documentation of milling began in 2008 and was observed on 21
occasions. No acute behavioral responses were documented. Mean group
size decreased during pile driving; however, this difference was not
statistically significant. There were significant differences in group
composition before and during pile driving between monthly CIBW
sighting rates and monthly pile driving rates with more white (i.e.,
older) animals being present during pile driving.
During PCT construction monitoring, behaviors of CIBWs groups were
compared by month and by construction activity (61 North Environmental,
2021). Little variability was evident in the behaviors recorded from
month to month, or between sightings that coincided with in-water pile
installation and removal and those that did not. One minor difference
was a slightly higher incidence of milling behavior during the periods
of no pile driving and slightly higher rates of traveling behavior
during periods when CIBWs were potential disturbed by pile driving.
Acoustically, Kendall et al. (2013) only recorded echolocation
clicks and no whistles or noisy vocalizations near construction
activity at the POA. CIBWs have been occasionally documented to forage
around Ship Creek (south of the POA) but, during pile driving, may
choose to move past the POA to other, potentially richer, feeding areas
further into Knik Arm (e.g., Six Mile Creek, Eagle River, Eklutna
River). These locations contain predictable salmon runs (ADF&G, 2010),
an important food source for CIBWs, and the timing of these runs has
been correlated with CIBW movements into the upper reaches of Knik Arm
(Ezer et al., 2013).
Auditory Masking
Since many marine mammals rely on sound to find prey, moderate
social interactions, and facilitate mating (Tyack, 2008), noise from
anthropogenic sound sources can interfere with these functions, but
only if the noise spectrum overlaps with the hearing sensitivity of the
marine mammal (Southall et al., 2007; Clark et al., 2009; Hatch et al.,
2012). Chronic exposure to excessive, though not high-intensity, noise
could cause masking at particular frequencies for marine mammals that
utilize sound for vital biological functions (Clark et al., 2009).
Acoustic masking is when other noises such as from human sources
interfere with animal detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, under certain circumstances,
marine mammals whose acoustical sensors or environment are being
severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction.
Masking, which can occur over large temporal and spatial scales,
can potentially affect the species at population, community, or even
ecosystem levels, as well as individual levels. Masking affects both
senders and receivers of the signals and could have long-term chronic
effects on marine mammal species and populations. Masking occurs at the
frequency band which the animals utilize so the frequency range of the
potentially masking sound is important in determining any potential
behavioral impacts. Pile driving generates low frequency sounds;
therefore, mysticete foraging is likely more affected than odontocetes
given very high frequency echolocation clicks (typically associated
with odontocete foraging) are likely unmasked to any significant
degree. However, lower frequency man-made sounds may affect
communication signals when they occur near the sound band and thus
reduce the communication space of animals (e.g., Clark et al., 2009)
and cause increased stress levels (e.g., Foote et al., 2004; Holt et
al., 2009).
Moreover, even within a given species, different types of man-made
noises may results in varying degrees of masking. For example, Erbe
(1997) and Erbe and Farmer (1998) analyzed the effect of masking of
beluga calls by exposing a trained beluga to icebreaker propeller
noise, an icebreaker's bubbler system, and ambient Arctic ice cracking
noise, and found that the latter was the least problematic for the
whale detecting the calls. Sheifele et al. (2005) studied a population
of belugas in the St. Lawrence River Estuary to determine whether
beluga vocalizations showed intensity changes in response to shipping
noise. This type of behavior has been observed in humans and is known
as the Lombard vocal response (Lombard, 1911). Sheifele et al. (2005)
demonstrated that shipping noise did cause belugas to vocalize louder.
The acoustic behavior of this same population of belugas was studied in
the presence of ferry and small boat noise. Lesage et al. (1999)
described more persistent vocal responses when whales were exposed to
the ferry than to the small-boat noise. These included a progressive
reduction in calling rate while vessels were approaching, an increase
in the repetition of specific calls, and a shift to higher frequency
bands used by vocalizing animals when vessels were close to the whales.
The authors concluded that these changes,
[[Page 31886]]
and the reduction in calling rate to almost silence, may reduce
communication efficiency which is critical for a species of a
gregarious nature. However, the authors also stated that because of the
gregarious nature of belugas, this ``would not pose a serious problem
for intraherd communication'' of belugas given the short distance
between group members, and concluded a noise source would have to be
very close to potentially limit any communication within the beluga
group (Lesage et al., 1999). However, increasing the intensity or
repetition rate, or shifting to higher frequencies when exposed to
shipping noise (from merchant, whale watching, ferry and small boats),
is indicative of an increase of energy costs (Bradbury and Vehrencamp,
1998).
Marine mammals in Cook Inlet are continuously exposed to
anthropogenic noise which may lead to some habituation but is also a
source of masking (Castellote et al., 2019, Mooney et al., 2020). A
subsample (8756 hours) of the acoustic recordings collected by the Cook
Inlet Beluga Acoustics research program in Cook Inlet, Alaska, from
July 2008 to May 2013, were analyzed to describe anthropogenic sources
of underwater noise, acoustic characteristics, and frequency of
occurrence and evaluate the potential for acoustic impact to CIBWs. As
described in Castellote et al., (2016), a total of 13 sources of noise
were identified: commercial ship, dredging, helicopter, jet aircraft
(commercial or non-fighter), jet aircraft (military fighter), outboard
engine (small skiffs, rafts), pile driving, propeller aircraft, sub-
bottom profiler, unclassified machinery (continuous mechanical sound;
e.g., engine), unidentified `clank' or `bang' (impulsive mechanical
sound; e.g., barge dumping), unidentified (unclassifiable anthropogenic
sound), unknown up- or down-sweep (modulated tone of mechanical origin;
e.g., hydraulics). A total of 6263 anthropogenic acoustic events were
detected and classified, which had a total duration of 1025 hours and
represented 11.7 percent of the sound recordings analyzed. There was
strong variability in source diversity, loudness, distribution, and
seasonal occurrence of noise, which reflects the many different
activities within the Cook Inlet. Cairn Point was the location where
the loudness and duration of commercial ship noise events were most
concentrated, due to activities at the POA. This specific source of
anthropogenic noise was present in the recordings from all months
analyzed, with highest levels in August. In addition to the
concentrated shipping noise at Cairn Point, a combination of unknown
noise classes occurred in this area, particularly during summer.
Specifically, unknown up or down sweeps, unidentified, unclassed
machinery, and unidentified clank or bang noise classes were all
documented. In contrast, Eagle River (north of the POA and where CIBWs
concentrate to forage) was the quietest of all sampled locations.
Sensitivity in CIBW hearing may make them more susceptible to
masking. The first empirical hearing data of a CIBW was recently
obtained by Mooney et al., (2020), who used auditory evoked potentials
to measure the hearing of a wild, stranded CIBW as part of its
rehabilitation assessment. The CIBW exhibited broadband (4-128 kHz) and
sensitive hearing (<80 dB) for a wide range of frequencies (16-80 kHz),
with the audiogram shape and waveforms generally reflective of a
sensitive odontocete's auditory system without substantial hearing loss
(Mooney et al., 2020). This sensitivity suggests that CIBWs are
susceptible to masking from a variety of anthropogenic sources in Cook
Inlet.
Potential Pile Driving Effects on Prey--Pile driving produces
continuous, non-impulsive (i.e., vibratory pile driving) sounds and
intermittent, pulsed (i.e., impact driving) sounds. Fish react to
sounds that are especially strong and/or intermittent low-frequency
sounds. Short duration, sharp sounds can cause overt or subtle changes
in fish behavior and local distribution. Hastings and Popper (2005)
identified several studies that suggest fish may relocate to avoid
certain areas of sound energy. Additional studies have documented
effects of pile driving on fish, although several are based on studies
in support of large, multiyear bridge construction projects (e.g.,
Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound pressure
levels (SPLs) of sufficient strength have been known to cause injury to
fish and fish mortality (summarized in Popper et al., 2014). The most
likely impact to fish from pile driving activities at the project area
would be temporary behavioral avoidance of the area. The duration of
fish avoidance of this area after pile driving stops is unknown, but a
rapid return to normal recruitment, distribution and behavior is
anticipated.
As discussed in the Marine Mammal section above, NMFS designated
CIBW critical habitat in Knik Arm. Knik Arm is Type 1 habitat for the
CIBWs, which means it is the most valuable, used intensively by CIBWs
from spring through fall for foraging and nursery habitat. However, the
POA, the adjacent navigation channel, and the turning basin were
excluded from critical habitat designation due to national security
concerns (76 FR 20180; April 11, 2011). Foraging primarily occurs at
river mouths (e.g., Susitna Delta, Eagle River flats) which are
unlikely to be influenced by pile driving activities. The Susitna Delta
is more than 20 km from the POA and Cairn Point is likely to impede any
pile driving noise from propagating into northern Knik Arm. Of the 245
CIBW groups observed during PCT construction monitoring, only two
groups were suspected to be feeding (61 North Environmental, 2021). One
of these groups (n = 4 CIBWs) was observed on May 7, 2020, a non-pile
driving day, approximately 142 m away from the PCT. The other group (n
= 3 CIBWs) was observed on July 14, 2020 during impact installation of
an attenuated 48-inch pile. These CIBWs were suspected to be foraging
in Bootleggers Cove, approximately 1,399 m way from the PCT and outside
the respective Level B harassment zone (824 m). It was unclear whether
or not feeding occurred during pile driving activities (61 North
Environmental, 2021).
Acoustic habitat is the soundscape which encompasses all of the
sound present in a particular location and time, as a whole, when
considered from the perspective of the animals experiencing it. Animals
produce sound for, or listen for sounds produced by, conspecifics
(communication during feeding, mating, and other social activities),
other animals (finding prey or avoiding predators) and the physical
environment (finding suitable habitats, navigating). Together, sounds
made by animals and the geophysical environment (e.g., produced by
earthquakes, lightning, wind, rain, waves) make up the natural
contributions to the total acoustics of a place. These acoustic
conditions, termed acoustic habitat, are one attribute of an animal's
total habitat. Soundscapes are also defined by, and acoustic habitat
influenced by, the total contribution of anthropogenic sound. This may
include incidental emissions from sources such as vessel traffic or may
be intentionally introduced to the marine environment for data
acquisition purposes (as in the use of airgun arrays or other sources).
Anthropogenic noise varies widely in its frequency content, duration,
and loudness and these characteristics greatly influence the potential
habitat-mediated effects to marine mammals (please see also the
[[Page 31887]]
previous discussion on masking under ``Acoustic Effects''), which may
range from local effects for brief periods of time to chronic effects
over large areas and for long durations. Depending on the extent of
effects to habitat, animals may alter their communications signals
(thereby potentially expending additional energy) or miss acoustic cues
(either conspecific or adventitious). For more detail on these concepts
see, e.g., Barber et al., 2010; Pijanowski et al., 2011; Francis and
Barber, 2013; Lillis et al., 2014.
CIBW foraging habitat is limited at the POA given the highly
industrialized area. However, foraging habitat exists near the POA,
including Ship Creek and to the north of Cairn Point. Potential impacts
to foraging habitat include increased turbidity and elevation in noise
levels during pile driving. While the POA is building a new dock, it is
removing the float and gangway of the existing dock and permanent
impacts from the presence of the new dock are negligible. Here, we
focus on construction impacts such as increased turbidity and reference
the section on acoustic habitat impacts above.
Pile installation may temporarily increase turbidity resulting from
suspended sediments. Any increases would be temporary, localized, and
minimal. POA must comply with state water quality standards during
these operations by limiting the extent of turbidity to the immediate
project area. In general, turbidity associated with pile installation
is localized to about a 25-foot (7.6 m) radius around the pile (Everitt
et al., 1980). Cetaceans are not expected to be close enough to the
project activity areas to experience effects of turbidity, and any
small cetaceans and pinnipeds could avoid localized areas of turbidity.
Therefore, the impact from increased turbidity levels is expected to be
discountable to marine mammals. No turbidity impacts to Ship Creek or
critical CIBW foraging habitats are anticipated.
In summary, activities associated with the proposed SFD project are
not likely to have a permanent, adverse effect on marine mammal habitat
or populations of fish species or on the quality of acoustic habitat.
Marine mammals may choose to not forage in close proximity to the SFD
site during pile driving; however, the POA is not a critical foraging
location for any marine mammal species. As discussed above, harbor
seals primarily use Ship Creek as foraging habitat within Knik Arm.
CIBWs utilize Eagle Bay and rivers north of the POA which are not
expected to be ensonified by the SFD project. Therefore, no impacts to
critical foraging grounds are anticipated.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as pile
driving has the potential to result in disruption of behavioral
patterns for individual marine mammals, either directly or as a result
of TTS. There is also some potential for auditory injury (Level A
harassment) to result, primarily for mysticetes, high frequency
species, and phocids because predicted auditory injury zones are larger
than for mid-frequency species and otariids. Auditory injury is
unlikely to occur for mid-frequency species and otariids. The proposed
mitigation and monitoring measures are expected to minimize the
severity of the taking to the extent practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the proposed take
estimate.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 [mu]Pa (root mean square; rms) for
continuous (e.g., vibratory pile-driving, drilling) and above 160 dB re
1 [mu]Pa (rms) for non-explosive impulsive (e.g., seismic airguns) or
intermittent (e.g., scientific sonar) sources. This take estimation
includes disruption of behavioral patterns resulting directly in
response to noise exposure (e.g., avoidance), as well as that resulting
indirectly from associated impacts such as TTS or masking. However,
ambient noise levels within Knik Arm are above the 120-dB threshold,
and therefore, for purposes of this analysis, NMFS considers received
levels above those of the measured ambient noise (122.2 dB) to
constitute Level B harassment of marine mammals incidental to
continuous noise, including vibratory pile driving.
Results from recent acoustic monitoring conducted at the port are
presented in Austin et al. (2016) and Denes et al. (2016) wherein noise
levels were measured in absence of pile driving from May 27 through May
30, 2016 at two locations: Ambient-Dock and Ambient-Offshore. NMFS
considers the median sound levels to be most appropriate when
considering background noise levels for purposes of
[[Page 31888]]
evaluating the potential impacts of the POA's SFD Project on marine
mammals (NMFS, 2012). By using the median value, which is the 50th
percentile of the measurements, for ambient noise level, one will be
able to eliminate the few transient loud identifiable events that do
not represent the true ambient condition of the area. This is relevant
because during two of the four days (50 percent) when background
measurement data were being collected, the U.S. Army Corps of Engineers
was dredging Terminal 3 (located just north of the Ambient-Offshore
hydrophone) for 24 hours per day with two 1-hour breaks for crew
change. On the last two days of data collection, no dredging was
occurring. Therefore, the median provides a better representation of
background noise levels when the SFD project would be occurring. With
regard to spatial considerations of the measurements, the Ambient-
Offshore location is most applicable to this discussion (NMFS, 2012).
The median ambient noise level collected over four days at the end of
May at the Ambient-Offshore hydrophone was 122.2 dB. We note the
Ambient-Dock location was quieter, with a median of 117 dB; however,
that hydrophone was placed very close to the dock and not where we
would expect Level B harassment to occur given mitigation measures
(e.g., shut downs). We also recognize that during Phase 1 PCT acoustic
monitoring, noise levels in Knik Arm absent pile driving were collected
(Reyff et al., 2021); however, the Phase 1 PCT IHA did not require
ambient noise measurements to be collected. These measurements were not
collected in accordance to NMFS (2012) guidance for measuring ambient
noise and thus cannot be used here for that purpose. If additional data
collected in the future warrant revisiting this issue, NMFS may adjust
the 122.2 dB rms Level B harassment threshold.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (NMFS, 2018) identifies dual criteria to
assess auditory injury (Level A harassment) to five different marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
The POA's proposed activity includes the use of non-impulsive
(vibratory pile driving) sources.
These thresholds are provided in Table 4 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>.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1; Lpk,flat: 219 dB; Cell 2; LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3; Lpk,flat: 230 dB; Cell 4; LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5; Lpk,flat: 202 dB; Cell 6; LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7; Lpk,flat: 218 dB; Cell 8; LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9; Lpk,flat: 232 dB; Cell 10; LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The estimated sound source levels (SSL) proposed by the POA and
used in this assessment for vibratory installation of attenuated piles
are based on sound levels of 24-inch and 36-inch piles measured during
a sound source verification (SSV) study conducted during Phase 1 of the
POA's 2020 PCT project (Reyff et al., 2021). For the 24-inch template
piles, SSLs measured for 24-inch PCT template piles by Reyff et al.
(2021) were selected for use as a proxy for 24-inch SFD template piles
based on anticipated pile function (Table 5). These piles were driven
for 19.2 to 25.6 minutes, using an APE 200-6 vibratory hammer and a
confined bubble curtain (Reyff et al., 2021). For the 36-inch template
piles, SSLs are assumed to be similar to the SSLs measured for 36-inch
trestle piles installed during PCT construction (note no 36-inch
template piles were measured in Reyffe et al., 2021) (Table 5). These
piles were installed with a confined bubble curtain using an APE 300-6
vibratory hammer; driving times ranged from 22.1 to 36.4 minutes. It is
assumed that SLLs during pile installation and removal for both pile
sizes will be similar.
No unattenuated 24-inch or 36-inch piles were installed during
either the TPP (Austin et al., 2016) or PCT SSV projects (Reyeff et
al., 2021). Instead, SSL measurements collected during marine
construction projects conducted by the U.S. Navy for the Naval Base
Kitsap at Bangor EHW-2 Project (U.S. Navy, 2015), which were installed
at similar depths and in a similar marine environment, were used as
proxies for vibratory and impact installation of unattenuated piles for
the SFD project (Table 5). It is assumed that SSLs during vibratory
pile installation and removal will be similar.
SSLs measurements for attenuated 24-inch and 36-inch piles driven
with an impact hammer also were not measured during either the TPP
(Austin et al., 2016) or PCT SSV projects (Reyeff et al., 2021). SSL
measurements for impact
[[Page 31889]]
installation made by Ryeff et al. (2021) were on piles using a confined
bubble curtain system with 48-inch piles; whereas, an unconfined system
is proposed with smaller piles for the SFD. In a confined bubble
curtain system, the bubbles are confined to the area around the pile
with a flexible material or rigid pipe; however, in an unconfined
bubble curtain system, there is no such system for restraining the
bubbles (NAVFAC SW, 2020). Unconfined bubble curtain performance is
highly variable and effectiveness depends on the system design and on-
site conditions such as water depth, water current velocity, substrate
and underlying geology. The unconfined systems typically consist of
vertically stacked bubble rings, while the confined systems are a
single ring at the bottom placed inside a casing that encompasses the
pile. The U.S. Navy (2015) summarized several studies which
demonstrated that unconfined bubble curtains performance can be
effective in attenuating underwater noise from impact pile
installation. They found bubble curtain performance to be highly
variable, but based on information from the Bangor Naval Base Test Pile
Program, found an average peak SPL reduction of 8 dB to 10 dB at 10 m
would be an achievable level of attenuation for steel pipe piles of 36-
and 48-inches in diameter. The efficiency of bubble curtains with 24-
inch piles was not examined by the U.S. Navy (2015). Based on these
analyses, and the effect that local currents may have on the
distribution of bubbles and thus effectiveness of an unconfined bubble
curtain, NMFS conservatively applies a 7 dB reduction to the U.S. Navy
(2015) unattenuated SSLs (Table 5) for attenuated 24-inch and 36-inch
piles during impact pile driving (Table 5). These SSLs are consistent
with SSLs previously proposed and authorized by NMFS for POA impact
pile driving of 24-inch and 36-inch piles (e.g., PCT Final IHA [85 FR
19294]). Rationale for using a 7 dB reduction has further been provided
on June 19, 2019, in 84 FR 28474 and on November 25, 2019, in 84 FR
64833. This reduction is more conservative than the confined bubble
curtain efficacy reported by Reyff et al. (2021), which ranged from 9
to 11 dB for peak, rms, and SEL single strike measurements.
The TL coefficients reported in the PCT SSV are highly variable and
are generally lower than values previously reported and used in the
region. For example, Reyff et al. (2021) reported unweighted
transmission loss coefficients ranging from 8.9 to 16.3 dB SEL and 7.0
to 16.7 dB rms for impact driving 48-inch attenuated piles. In the PCT
Final IHA (85 FR 19294), the POA proposed, and NMFS applied, a TL rate
of 16.85 dB SEL for assessing potential for Level A harassment from
impact pile driving and a TL rate of 18.35 dB rms when assessing
potential for Level B harassment from impact pile driving for based on
Austin et al. (2016) measurements recorded during the TPP on 48-in
piles. Higher TL rates in Knik Arm are supported by additional studies,
such as by [Scaron]irovi[cacute] and Kendall (2009), who reported a TL
of 16.4 dB during impact hammer driving during passive acoustic
monitoring of the POA Marine Terminal Redevelopment Project, and by
Blackwell (2005) who reported TLs ranging from 16--18 dB SEL and 21.8
dB rms for impact and vibratory installation of 36-inch piles,
respectively, during modifications made to the Port MacKenzie dock.
After careful inspection of the data presented in the Reyff et al.,
study (including relevant spectrograms), NMFS is concerned that flow
noise in the far field measurements is negatively biasing the
regressions derived to infer TL rates. While Reyff et al. (2021)
discuss attempts they made to remove flow noise from their
calculations, NMFS could not conclude that these attempts adequately
removed flow noise from their measurements. Relevant to the SFD, the TL
calculations of individual vibratory installation of 24-inch template
piles and 36-inch trestle piles reported by Reyff et al. (2021) were
also highly variable ranging from 12.5 to 16.6 dB rms and 14.4 to 17.2
dB rms, respectively. Given this variability and previous data
suggesting higher TL rates, NMFS has preliminarily determined that
applying a practical spreading loss model (15logR) to ensonified area
calculations is most likely the representative scenario in Knik Arm
(Table 5). The 15 TL coefficient also falls within the range of TL
coefficients reported in Reyff et al. (2021). We note the POA will
conduct additional acoustic monitoring during Phase II of the PCT in
2021 (prior to when the SFD project will commence) and, if warranted,
these assumptions may be adjusted and resulting harassment isopleths
modified.
Table 5--Estimated Sound Source Levels and Transmission Loss Coefficients With and Without a Bubble Curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile size Unattenuated
Bubble curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Sound level at 10 m
TL coefficient
Sound level at 10 m
TL coefficient
(dB rms)
(dB rms)
(dB rms)
(dB rms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch................................... \a\ 166.0
\c\ 15.0
\b\ 161.4
\c\ 15.0
24-inch................................... \a\ 161.0
\c\ 15.0
\b\ 158.5
\c\ 15.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Unattenuated
Bubble curtain
-------------------------------------------------------------------------------------------------------------
Sound level at 10 m
TL coefficient
Sound level at 10 m
TL coefficient
-------------------------------------------------------------------------------------------------------------
dB rms dB SEL dB Peak dB rms dB SEL dB rms dB SEL dB peak dB rms dB SEL
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch................................... \a\ 194.0 \a\ 184.0 \a\ 211.0 \c\ 15.0 \c\ 15.0 \a\ 187.0 \a\ 177.0 \a\ 204.0 \c\ 15.0 \c\ 15.0
24-inch................................... \a\ 193.0 \a\ 181.0 \a\ 210.0 \c\ 15.0 \c\ 15.0 \a\ 186.0 \a\ 174.0 \a\ 203.0 \c\ 15.0 \c\ 15.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ U.S. Navy 2015.
\b\ Reyff et al., 2021.
\c\ Practical spreading loss model.
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
[[Page 31890]]
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources (such as pile
driving), NMFS User Spreadsheet predicts the distance at which, if a
marine mammal remained at that distance the whole duration of the
activity, it would incur PTS. Inputs used in the User Spreadsheet, and
the resulting isopleths are reported below in Table 6.
Table 6--NMFS User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
24-Inch 24-Inch (bubble 36-Inch 36-Inch (bubble
(unattenuated) curtain) (unattenuated) curtain)
----------------------------------------------------------------------------------------------------------------
User Spreadsheet Input: Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............ A.1) Non-Impul, A.1) Non-Impul, A.1) Non-Impul, A.1) Non-Impul,
Stat, Cont. Stat, Cont. Stat, Cont. Stat, Cont.
Source Level (SPL RMS).......... 161............... 158.5............. 166............... 161.4.
Transmission Loss Coefficient... 15................ 15................ 15................ 15.
Weighting Factor Adjustment 2.5............... 2.5............... 2.5............... 2.5.
(kHz).
Time to install/remove single 45/75............. 45/75............. 45/75............. 45/75.
pile (minutes).
Piles to install/remove per day. 1/1............... 1-2/1-3........... 1/1............... 1-3/1-3.
----------------------------------------------------------------------------------------------------------------
User Spreadsheet Input: Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............ E.1) Impact pile E.1) Impact pile E.1) Impact pile E.1) Impact pile
driving. driving. driving. driving.
Source Level (Single Strike/shot 181............... 174............... 184............... 177.
SEL).
Transmission Loss Coefficient... 15................ 15................ 15................ 15.
Weighting Factor Adjustment 2................. 2................. 2................. 2.
(kHz).
Number of strikes pile.......... 1000.............. 1000.............. 1000.............. 1000.
Piles per day................... 1................. 1................. 1................. 1.
----------------------------------------------------------------------------------------------------------------
To calculate the Level B harassment isopleths, NMFS considered
SPLrms source levels and the corresponding TL coefficients (dB rms;
Table 5) for impact and vibratory pile driving, respectively. The
resulting Level A harassment and Level B harassment isopleths are
presented in Table 7.
Table 7--Distances to Level A Harassment, by Hearing Group, and Level B Harassment Thresholds per Pile Type and Installation Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment (m) Level A
--------------------------------------------- harassment
Hammer type Piles areas Level B
Pile size Attenuation (installation/ per day (km\2\) all harassment
removal) LF MF HF PW OW hearing (m)
groups
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch......................... Bubble Curtain.... Vibratory 1 4 1 6 3 1 <0.01 2,631
(Installation).
2 7 1 9 4 1
Vibratory 1 6 1 8 4 1
(Removal).
3 12 1 17 7 1
Impact 1 251 9 299 135 10 <0.19 542
(Installation).
Unattenuated...... Vibratory 1 6 1 9 4 1 <0.01 3,861
(Installation).
Vibratory 1 8 1 12 5 1
(Removal).
Impact 1 735 27 876 394 29 <1.34 1,585
(Installation).
36-inch......................... Bubble Curtain.... Vibratory 1 6 1 9 4 1 <0.01 4,106
(Installation).
2 10 1 15 6 1
3 13 2 19 8 1
Vibratory 1 9 1 13 6 1
(Removal).
3 18 2 26 11 1
Impact 1 398 15 474 213 16 <0.76 631
(Installation).
Unattenuated...... Vibratory 1 13 2 18 8 1 <0.01 8,318
(Installation).
Vibratory 1 18 2 26 11 1
(Removal).
Impact 1 1,165 42 1,387 624 46 <3.14 1,848
(Installation).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
For all species of cetaceans other than CIBWs, density data is not
available for upper Cook Inlet. Therefore, the POA relied on marine
mammal monitoring data collected during past POA projects. These data
cover the POAs construction season (April through November) across
multiple years. Calculations used to estimate exposure from pile
installation for all marine mammals is described below.
Humpback Whales
Sightings of humpback whales in the project area are rare, and the
potential risk of exposure of a humpback whale to sounds exceeding the
Level B harassment threshold is low. Few, if any, humpback whales are
expected to approach the project area. However, there were two
sightings in 2017 of what
[[Page 31891]]
was likely a single individual at the Ship Creek Boat Launch (ABR Inc.,
2017) which is located south of the project area. Based on these data,
the POA conservatively estimates that up to two individuals could be
behaviorally harassed during the 24 days of pile driving for the SFD.
This could include sighting a cow-calf pair on multiple days or
multiple sightings of single humpback whales. No Level A harassment
take of humpback whales is anticipated or proposed to be authorized.
Killer Whales
Few, if any, killer whales are expected to approach the project
area. No killer whales were sighted during previous monitoring programs
for the Knik Arm Crossing and POA construction projects, including the
2016 TPP or during Phase 1 of the PCT project in 20202. The infrequent
sightings of killer whales that are reported in upper Cook Inlet tend
to occur when their primary prey (anadromous fish for resident killer
whales and CIBWs for transient killer whales) are also in the area
(Shelden et al., 2003). Previous sightings of transient killer whales
have documented pod sizes in upper Cook Inlet between one and six
individuals (Shelden et al., 2003). The potential for exposure of
killer whales within the Level B harassment isopleths is anticipated to
be extremely low. Level B harassment take is conservatively estimated
at no more than one small pod (6 individuals). No Level A harassment
take for killer whales is anticipated or proposed to be authorized due
to the small Level A harassment zones (Table 7) and implementation of a
100 m shutdown which is larger than Level A harassment isopleths, and
described below in the Proposed Mitigation section.
Harbor Porpoise
Previous monitoring data at the POA were used to evaluate daily
sighting rates for harbor porpoises in the project area. During most
years of monitoring, no harbor porpoises were observed; however, during
Phase 1 of the PCT project (2020), 18 individuals (15 groups) were
observed near the POA, with group sizes ranging from 1-2 individuals.
The highest daily sighting rate for any recorded year during pile
installation and removal associated with the PCT was an average of 0.09
harbor porpoise per day during 2009 construction monitoring, but this
value may not account for increased sightings in Upper Cook Inlet or
range extensions (Shelden et al., 2014). Therefore, the POA estimates
that one harbor porpoise could be observed every 2 days of pile
driving. Based on this assumption, the POA has requested, and NMFS is
proposing to authorize, twelve Level B harassment exposures during the
24 days of pile driving.
Harbor porpoises are relatively small cetaceans that move at high
velocities, which can make their detection and identification at great
distances difficult. Despite this, PSOs during Phase 1 PCT construction
monitoring (2020) were able to detect harbor porpoises as far as 6,486
m from the PCT, indicating that the monitoring methods detailed in the
Final IHAs for Phase 1 and Phase 2 PCT construction (85 FR 19294), (and
described below in the Proposed Mitigation section for the SFD) allowed
for harbor porpoises to be detected at great distances. Therefore, no
Level A harassment take for harbor porpoises is anticipated or proposed
to be authorized for the SFD. The POA anticipates that the majority of
piles will be driven using vibratory methods. Using the NMFS User
Spreadsheet, vibratory driving 24-inch and 36-inch piles results in
Level A harassment isopleths that are smaller than the proposed 100 m
shutdown zone, described below in the Proposed Mitigation section (<=26
m; Table 7). The Level A harassment isopleths calculated using the NMFS
User Spreadsheet for impact driving 24-inch and 36-inch piles are
larger than this 100-m shutdown zone (<=1,387 m; Table 7); however,
Level A harassment isopleths consider long durations and harbor
porpoise are likely moving through the area, if present, not lingering.
Further few harbor porpoises are expected to approach the project area
and are likely to be sighted prior to entering the Level A harassment
zone. During Phase 1 PCT construction monitoring (2020) only five
harbor porpoises were observed near the PCT and within the largest
Level A harassment zone for SFD (1,387 m; Table 7). Given that the POA
anticipates that only a small number of piles (up to five), may be
driven with an impact hammer (requiring up to 20 minutes of impact
installation each at 1 pile per day), the likelihood that harbor
porpoises will be in these larger zones is minimized. Accounting for
measures described below in the Proposed Mitigation section below and
the low likelihood that individual harbor porpoises would appear
undetected within the Level A harassment zones, we agree with the POA
and do not authorize any Level A harassment takes of harbor porpoises
during the construction of the SFD.
Steller Sea Lion
Steller sea lions are anticipated to be encountered in low numbers,
if at all, within the project area. Three sightings of what was likely
a single individual occurred in the project area in 2009, two sightings
occurred in 2016, one occurred in 2019, and up to six individuals were
observed in 2020 (4 in May and 2 in June). Based on observations in
2016, the POA anticipates an exposure rate of two individuals every 19
days during SFD pile installation and removal. Based on this rate, the
POA anticipates that there could be up to four harassment exposures of
Steller sea lions during the 24 days of SFD pile installation and
removal.
Sea lions are known to travel at high speeds, in rapidly changing
directions, and have the potential to be counted multiple times.
Because of this the POA anticipates that, despite all precautions, sea
lions could enter the Level A harassment zone before a shutdown could
be fully implemented. For example, in 2016 during the POA Test Pile
Program, a Steller sea lion was first sighted next to a work boat and
within the Level A harassment zone. Nine PSOs had been monitoring for
the presence of marine mammals near the construction activities at this
time, but they did not observe the approaching sea lion. Sea lions are
known to be curious and willing to approach human activity closely, and
they can swim with a low profile. The incident was recorded as a Level
A harassment take and raises concern for the POA that a sighting of a
Steller sea lion within the Level A harassment zones, while unlikely,
could occur. While Level A harassment takes are unlikely given the low
likelihood of sea lions in the project area, the small Level A
harassment isopleths (<46 m; Table 7), and the proposed mitigation
measures, including the implementation of shutdown zones and the use of
PSOs, we propose to authorize the POA's request that a small number of
Steller sea lions could be exposed to Level A harassment levels.
Therefore, we propose that two Steller sea lions could be exposed to
Level A harassment levels and 2 Steller sea lions could be exposed to
Level B harassment levels.
Harbor Seals
No known harbor seal haulout or pupping sites occur in the vicinity
of the POA; therefore, exposure of harbor seals to in-air noise is not
considered in this application, and no take for in-air exposure is
requested. Harbor seals are not known to reside in the project area,
but they are seen regularly near the
[[Page 31892]]
mouth of Ship Creek when salmon are running, from July through
September. With the exception of newborn pups, all ages and sexes of
harbor seals could occur in the project area during construction of the
SFD. Any harassment of harbor seals during pile installation would
involve a limited number of individuals that may potentially swim
through the project area or linger near Ship Creek.
Marine mammal monitoring data were used to examine hourly sighting
rates for harbor seals in the project area. Sighting rates of harbor
seals were highly variable and appeared to have increased during
monitoring between 2005 and 2020 (See Table 4-1 in POA's application).
It is unknown whether any potential increase was due to local
population increases or habituation to ongoing construction activities.
The highest monthly hourly sighting rate (rounded) observed during
previous monitoring at the POA was used to quantify take of harbor
seals for pile installation associated with the SFD. This occurred in
2020 during Phase 1 PCT construction monitoring, when harbor seals were
observed from May through September. A total of 340 harbor seals were
observed over 1,237.7 hours of monitoring, at a rate of 0.3 harbor
seals per hour. The maximum monthly hourly sighting rate occurred in
September and was 0.51 harbor seals per hour. Based on these data, the
POA estimates that approximately 1 harbor seal may be observed near the
project per hour of hammer use. During the 21 hours of anticipated pile
installation and removal, the POA estimates that up 21 harbor seals
will be exposed to in-water noise levels exceeding harassment
thresholds for pile installation and removal during SFD construction.
All efforts will be taken to shut down prior to a harbor seal
entering the 100-m shutdown zone and prior to a harbor seal entering
the Level A harassment zones. However, harbor seals often are curious
of onshore activities, and previous monitoring suggests that this
species may mill at the mouth of Ship Creek. It is important to note
that the mouth of Ship Creek is about 700 m from the southern end of
the SFD and is outside the Level A harassment zones for harbor seals
during both unattenuated and attenuated vibratory and impact pile
installation and removal (Table 7). While exposure is anticipated to be
minimized because pile installation and removal will occur
intermittently over the short construction period, the POA is
requesting Level A harassment take for a small number of harbor seals,
given the potential difficulty of detecting harbor seals and their
consistent use of the area. Given that 30 harbor seals (8.6 percent) of
all harbor seals and unidentified pinnipeds were detected within 624 m,
the largest Level A harassment zone for SFD, during PCT Phase 1
construction monitoring (61 North Environmental, 2021), POA requests
and NMFS proposes to authorize that two harbor seals (8.6 percent of 21
exposures rounded up) could be exposed to Level A harassment levels and
19 harbor seals could be exposed to Level B harassment levels.
Beluga Whales
For CIBWs, we looked at several sources of information on marine
mammal occurrence in upper Cook Inlet to determine how best to estimate
the potential for exposure to pile driving noise from the SFD Project.
In their application, the POA estimated Level B harassment take
following methods outlined in the PCT final IHA (85 FR 19294), which
relies on monitoring data of CIBWs published in Kendall and Cornick
(2015). For the SFD application, POA also considered monitoring data of
CIBWs collected during Phase 1 of the PCT project (61 North
Environmental, 2021). These data sets (Kendall and Cornick, 2015, and
61 North Environmental, 2021) cover all months the POA may be
conducting pile driving for the SFD and they are based on all animals
observed during scientific monitoring within the proximity of the SFD
regardless of distance. Hourly sighting rates for CIBWs for each
calendar month were calculated using documented hours of observation
and CIBW sightings from April through November for 2005, 2006, 2008 and
2009 (Kendall and Cornick, 2015) and 2020 (61 North Environmental,
2021) (Table 8). The highest calculated monthly hourly sighting rate of
0.94 whales per hour was used to calculate potential CIBW exposures (21
hours of pile installation and removal multiplied by 0.94 whales/hour).
Using this method, the POA estimated that 20 CIBWs (rounded from 19.75)
could be exposed to the Level B harassment level during pile
installation and removal associated with the construction of the SFD.
These calculations assume no mitigation and that all animals observed
would enter a given Level B harassment zone during pile driving.
Table 8--Summary of CIBWs Sighting Data From April-November 2005-2009 and April-November 2020
----------------------------------------------------------------------------------------------------------------
Month Total hours Total groups Total whales Whales/hour
----------------------------------------------------------------------------------------------------------------
April........................................... 52.50 13 35 0.67
May............................................. 457.40 53 208 0.45
June............................................ 597.77 37 122 0.20
July............................................ 552.67 14 27 0.05
August.......................................... 577.30 120 543 0.94
September....................................... 533.03 124 445 0.83
October......................................... 450.70 9 22 0.05
November........................................ 346.63 52 272 0.78
----------------------------------------------------------------------------------------------------------------
Data compiled from Kendall and Cornick (2015) and (61 North Environmental, 2021).
To more accurately estimate potential exposures than simply using
the monthly sighting rate data, which does not account for any
mitigation, POA followed methods described by NMFS for the PCT Final
IHA (85 FR 19294), which looked at previous monitoring results at the
POA in relation to authorized take numbers. Between 2008 and 2012, NMFS
authorized 34 CIBW takes per year to POA, with mitigation measures
similar to the measures proposed here. The percent of the authorized
takes documented during this time period ranged from 12 to 59 percent
with an average of 36 percent (Table 9). In 2020, NMFS authorized 55
CIBW takes in Phase 1 of the PCT project, with mitigation and
monitoring measures that are consistent with those proposed for the SFD
and described below in the Proposed Mitigation section. The percent of
the authorized takes that were documented was 47 percent (26 out of 55
exposures; 61 North Environmental, 2021; Table 9). Given that there was
extensive monitoring occurring across all IHAs (with effort intensified
in 2020), we
[[Page 31893]]
believe there is little potential that animals were taken but not
observed.
Table 9--Authorized and Reported CIBW Takes During POA Activities From 2009-2012 and 2020
----------------------------------------------------------------------------------------------------------------
Percent of
ITA effective dates Reported takes Authorized authorized
takes takes
----------------------------------------------------------------------------------------------------------------
15 July 2008-14 July 2009....................................... 12 34 35
15 July 2009-14 July 2010....................................... 20 34 59
15 July 2010-14 July 2011....................................... 13 34 38
15 July 2011-14 July 2012....................................... 4 34 12
1 April 2020-31 March 2021...................................... 26 55 47
----------------------------------------------------------------------------------------------------------------
As described in the POA's application and in more detail in the
Proposed Mitigation section, mitigation measures have been designed to
reduce Level B harassment take as well avoid Level A harassment take.
We recognize that in certain situations, pile driving may not be able
to be shut down prior to whales entering the Level B harassment zone
due to safety concerns. During previous monitoring, sometimes CIBWs
were initially sighted outside of the harassment zone and shutdown was
called, but the CIBWs swam into the harassment zone before activities
could be halted, and exposure within the harassment zone occurred. For
example, on September 14, 2009, a construction observer sighted a CIBW
just outside the harassment zone, moving quickly towards the 1,300 m
Level B harassment zone during vibratory pile driving. The animal
entered the harassment zone before construction activity could be shut
down (ICRC, 2010). On other occasions, CIBWs were initially observed
when they surfaced within the harassment zone. For example, on November
4, 2009, 15 CIBWs were initially sighted approximately 950 m north of
the project site near the shore, and then they surfaced in the Level B
harassment zone during vibratory pile driving (ICRC, 2010).
Construction activities were immediately shut down, but the 15 CIBWs
were nevertheless exposed within the Level B harassment zone. During
Phase 1 of the PCT project all of the recorded takes (n = 26) were
instances where the whales were first sighted within the Level B
harassment zone, prompting shutdown procedures. Most of these exposures
(21 of 26) occurred when the CIBWs first appeared near the northern
station, just south of Cairn Point (61 North Environmental, 2021). For
example, on November 21, 2020 one CIBW was sighted in front of the
north PSO station, located just south of Cairn Point, traveling south
during vibratory removal of an attenuated 36-inch pile and a shutdown
was called immediately (61 North Environmental, 2021). In 2020, the
northern station did not have visibility of the near shoreline north of
Cairn Point. As a result, CIBWs traveling south during ebb tides around
Cairn Point were often inside of the Level B harassment zone upon first
sighting (61 North Environmental, 2021). As described below in the
Proposed Monitoring and Reporting section, mitigation and monitoring
approaches for the SFD project are modeled after the stipulations
outlined in the Final IHAs for Phase 1 and Phase 2 PCT construction (85
FR 19294), but one of the PSO stations will be moved to enhance
visibility to the north, especially near Cairn point. Therefore, we
believe the ability to detect whales and shut down prior to them
entering the Level B harassment zones will be better or consistent with
previous years.
To account for these mitigation measures, the POA then applied the
highest percentage of previous takes (59 percent) to ensure potential
impacts to CIBWs are adequately evaluated. After applying this
adjustment to account for potential exposures of CIBWs that would be
avoided by shutting down, the POA estimated that 12 CIBWs (20 whales *
0.59 = 11.80 whales; 12 rounded up) may be exposed to Level B
harassment during pile installation and removal. The POA and NMFS are
concerned, however, that this approach does not accurately reflect the
reality that CIBWs can travel in large groups. Large groups of CIBWs
have been seen swimming through the POA vicinity during POA monitoring
efforts. For example, during Phase 1 of the PCT, the mean group size
was 4.34 whales; however, 52 percent of observations were of groups
greater than the mean group size, with 5 percent of those 119 groups
being larger than 12 individuals, the number of exposures proposed by
POA (61 North Environmental, 2021).
To ensure that a large group of CIBWs would not result in the POA
using the majority or all of their take in one or two sightings, POA
buffered the exposure estimate detailed in the preceding by adding the
estimated size of a notional large group of CIBWs. The 95th percentile
is commonly used in statistics to evaluate risk. Therefore, to
determine the most appropriate size of a large group, the POA
calculated the 95 percentile group size of CIBWs observed during
Kendall and Cornick (2015) and 2020 Phase 1 PCT construction monitoring
(61 North Environmental, 2021); the same data used above to derive
hourly sighting rates (Table 8 and Figure 3). In this case, the 95th
percentile provides a conservative value that reduces the risk to the
POA of taking a large group of CIBWs and exceeding authorized take
levels. The 95th percentile of group size for the Kendall and Cornick
(2015) and the PCT Phase 1 monitoring data (61 North Environmental,
2021) is 12.0. This means that, of the 422 documented CIBW groups in
these data sets, 95 percent consisted of fewer than 12.0 whales; 5
percent of the groups consisted of more than 12.0. Considering large
group size, the POA requests and we propose to authorize 24 takes
(accounting for the 12 takes calculated following the methods outlined
for the PCT project that accounts for mitigation plus a group size of
12) of CIBWs incidental to pile driving for the SFD. Incorporation of
large groups into the CIBW exposure estimate is intended to reduce risk
to the POA of the unintentional take of a larger number of belugas than
would be authorized by using the proposed methods alone and thus
improve our estimate of exposure. No Level A harassment is expected or
proposed given the small Level A harassment zones for CIBWs (Table 7)
and the additional mitigation measures described in the Proposed
Mitigation section below specific to CIBWs, including the measure that
pile driving activities must shut down when any CIBW enters the
relevant Level B harassment zone.
[[Page 31894]]
[GRAPHIC] [TIFF OMITTED] TN15JN21.015
In summary, the total amount of Level A harassment and Level B
harassment proposed to be authorized for each marine mammal stock is
presented in Table 10.
Table 10--Proposed Amount of Take, by Stock and Harassment Type
----------------------------------------------------------------------------------------------------------------
Proposed authorized take
Species Stock -------------------------------- Percent of
Level A Level B stock
----------------------------------------------------------------------------------------------------------------
Humpback whale........................ Western N Pacific....... 0 2 0.19
Beluga whale.......................... Cook Inlet.............. 0 24 8.60
Killer whale.......................... Transient/Alaska 0 6 1.02/0.26
Resident.
Harbor porpoise....................... Gulf of Alaska.......... 0 12 0.04
Steller sea lion...................... Western................. 2 2 <0.01
Harbor seal........................... Cook Inlet/Shelikof..... 2 19 0.07
----------------------------------------------------------------------------------------------------------------
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for 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 the
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.
The POA presented mitigation measures in Section 11 of their
[[Page 31895]]
application that were modeled after the stipulations outlined in the
Final IHAs for Phase 1 and Phase 2 PCT construction (85 FR 19294),
which were successful in minimizing the total number and duration of
Level B harassment exposures for endangered CIBWs during Phase 1 PCT
Construction (61 North Environmental, 2021). These measures both reduce
noise into the aquatic environment and reduce the potential for CIBWs
to be adversely impacted from any unavoidable noise exposure.
A key mitigation measure NMFS considered for this project is
reducing noise levels propagating into the environment. The POA will
deploy an unconfined bubble curtain system during installation and
removal of plumb (vertical) 24- and 36-inch piles with a vibratory or
impact hammer. An unconfined bubble curtain is composed of an air
compressor(s), supply lines to deliver the air, distribution manifolds
or headers, perforated aeration pipe, and a frame. The frame
facilitates transport and placement of the system, keeps the aeration
pipes stable, and provides ballast to counteract the buoyancy of the
aeration pipes in operation. The air is released through a series of
vertically distributed bubble rings that create a cloud of bubbles that
act to impede and scatter sound, lowering the sound velocity. A
compressor provides a continuous supply of compressed air, which is
distributed among the layered bubble rings. Air is released from small
holes in the bubble rings to create a curtain of air bubbles
surrounding the pile. The curtain of air bubbles floating to the
surface inhibits the transmission of pile installation sounds into the
surrounding water column. The final design of the bubble curtain will
be determined by the Construction Contractor based on factors such as
water depth, current velocities, and pile sizes. However, the proposed
IHA requires the bubble curtain be operated in a manner consistent with
the following performance standards:
<bullet> The aeration pipe system will consist of multiple layers
of perforated pipe rings, stacked vertically in accordance with the
following depths: Two layers for water depths <5 m; four layers for
water depths 5 m to <10 m; seven layers for water depths 10 m to <15 m;
ten layers for water depths 15 m to <20 m; and thirteen layers for
water depths 20 m to <25 m;
<bullet> The pipes in all layers will be arranged in a geometric
pattern that will allow for the pile being driven to be completely
enclosed by bubbles for the full depth of the water column and with a
radial dimension such that the rings are no more than 0.5 m from the
outside surface of the pile;
<bullet> The lowest layer of perforated aeration pipe will be
designed to ensure contact with the substrate without burial and will
accommodate sloped conditions;
<bullet> Air holes will be 1.6 millimeters (\1/16\ inch) in
diameter and will be spaced approximately 20 millimeters (\3/4\ inch)
apart. Air holes with this size and spacing will be placed in four
adjacent rows along the pipe to provide uniform bubble flux;
<bullet> The system will provide a bubble flux of 3 cubic meters
(m\3\) per minute per linear meter of pipe in each layer (32.91 cubic
feet (ft\3\) per minute per linear foot of pipe in each layer). The
total volume of air per layer is the product of the bubble flux and the
circumference of the ring using the formula: Vt = 3.0 m\3\/min/m *
Circumference of the aeration ring in meters or Vt = 32.91 ft\3\/min/ft
* Circumference of the aeration ring in feet; and
<bullet> Meters must be provided as follows:
[cir] Pressure meters must be installed at all inlets to aeration
pipelines and at points of lowest pressure in each branch of the
aeration pipeline;
[cir] Flow meters must be installed in the main line at each
compressor and at each branch of the aeration pipelines at each inlet.
In applications where the feed line from the compressor is continuous
from the compressor to the aeration pipe inlet, the flow meter at the
compressor can be eliminated; and
[cir] Flow meters must be installed according to the manufacturer's
recommendation based on either laminar flow or non-laminar flow.
The bubble curtain will be used during installation and removal of
all plumb piles when water depth is great enough (approximately 3 m) to
deploy the bubble curtain. A bubble curtain will not be used with the
two battered piles due to the angle of installation. It is important to
note that a small number of piles could be installed or removed when
the pile location is de-watered (no water present) or when the water is
too shallow (<=3 m) to deploy the bubble curtain. The tides at the POA
have a mean range of about 8.0 m (26 ft) (NOAA, 2015), and low water
levels will prevent proper deployment and function of the bubble
curtain system. Piles that are driven at a location that is de-watered
will not use a bubble curtain, and marine mammal harassment zones will
not be monitored. When piles are installed or removed in water without
a bubble curtain because the pile orientation is battered, or if water
is too shallow (<=3 m) to deploy the bubble curtain, the unattenuated
Level A and Level B harassment zones for that hammer type and pile size
will be implemented.
In addition to noise attenuation devices, POA and NMFS considered
practicable work restrictions. Given the extensive Level B harassment
zone generated from the installation of the two unattenuated battered
piles, vibratory driving these large piles during peak CIBW season
poses an amount of risk and uncertainty to the degree that it should be
minimized. This August and September peak is confirmed through acoustic
monitoring (Castellote et al., 2020) and Phase 1 PCT construction
monitoring (61 North Environmental, 2021). Castellote et al. (2020) for
example indicate CIBWs appeared concentrated in the upper inlet year-
round, but particularly feeding in river mouths from April-December,
shifting their geographical foraging preferences from the Susitna River
region towards Knik Arm in mid-August, and dispersing towards the mid
inlet throughout the winter. Further, hourly sighting rates calculated
from monitoring data from Kendall and Cornick (2015) and Phase 1 of the
PCT (61 North Environmental, 2021) were highest in August and September
(0.94 and 0.83, respectively; Table 8). Therefore, vibratory driving
unattenuated battered piles (which have, by far, the largest Level B
harassment zones) will not occur during August or September. Further,
to minimize the potential for overlapping sound fields from multiple
stressors, the POA will not simultaneously operate two vibratory
hammers for either pile installation or removal. This measure is
designed to reduce simultaneous in-water noise exposure. Because impact
hammers will not likely be dropping at the same time, and to expedite
construction of the project to minimize pile driving during peak CIBW
abundance periods, NMFS is not proposing to restrict the operation of
two impact hammers at the same time. Given the small size of the
project and the plan to primarily drive hammers with a vibratory
hammer, the POA has indicated that it is highly unlikely that an impact
hammer and vibratory hammer or two impact hammers would operate
simultaneously during the SFD project.
Additional mitigation measures include the following, modeled after
the stipulations outlined in the Final IHAs for Phase 1 and Phase 2 PCT
construction (85 FR 19294):
For in-water construction involving heavy machinery activities
other than pile driving (e.g., use of barge-mounted
[[Page 31896]]
excavators), the POA will cease operations and reduce vessel speed to
the minimum level required to maintain steerage and safe working
conditions if a marine mammal approaches within 10 m of the equipment
or vessel.
POA must use soft start techniques when impact pile driving. Soft
start requires contractors to provide an initial set of three strikes
at reduced energy, followed by a thirty-second waiting period, then two
subsequent reduced energy strike sets. A soft start must be implemented
at the start of each day's impact pile driving and at any time
following cessation of impact pile driving for a period of thirty
minutes or longer. Soft starts will not be used for vibratory pile
installation and removal. PSOs shall begin observing for marine mammals
30 minutes before ``soft start'' or in-water pile installation or
removal begins.
The POA will conduct briefings for construction supervisors and
crews, the monitoring team, and POA staff prior to the start of all
pile installation and removal, and when new personnel join the work in
order to explain responsibilities, communication procedures, the marine
mammal monitoring protocol, and operational procedures.
The POA will employ PSOs per the Marine Mammal Monitoring Plan (see
Appendix A in the POA's application).
Marine mammal monitoring will take place from 30 minutes prior to
initiation of pile installation and removal through 30 minutes post-
completion of pile installation and removal. The Level B harassment
zone must be fully visible for 30 minutes before the zone can be
considered clear. Pile driving will commence when observers have
declared the shutdown zone clear of marine mammals or the mitigation
measures developed specifically for CIBWs (below) are satisfied. In the
event of a delay or shutdown of activity, marine mammal behavior will
be monitored and documented until the marine mammals leave the shutdown
zone of their own volition, at which point pile installation or removal
will begin. Further, NMFS requires that if pile driving has ceased for
more than 30 minutes within a day and monitoring is not occurring
during this break, another 30-minute pre-pile driving observation
period is required before pile driving may commence.
If a marine mammal is entering or is observed within an established
Level A harassment zone or shutdown zone, pile installation and removal
will be halted or delayed. Pile driving will not commence or resume
until either the animal has voluntarily left and been visually
confirmed 100 m beyond the shutdown zone and on a path away from such
zone, or 15 minutes (non- CIBWs) or 30 minutes (CIBWs) have passed
without subsequent detections.
If a species for which authorization has not been granted, or a
species for which authorization has been granted but the authorized
takes are met, is observed approaching or within the Level B harassment
zone, pile installation and removal will shut down immediately. Pile
driving will not resume until the animal has been confirmed to have
left the area or the 30 minute observation period has elapsed.
In addition to these measures which greatly reduce the potential
for harassment of all marine mammals and establish shutdown zones that
realistically reflect non-CIBW whale detectability, the following
additional mitigation measures have been proposed which would ensure
valuable protection and conservation of CIBWs:
Prior to the onset of pile driving, should a CIBW be observed
approaching the mouth of Knik Arm, pile driving will be delayed. An in-
bound pre-clearance line extends from Point Woronzof to approximately
2.5 kms west of Point McKenzie. Pile driving may commence once the
whale(s) moves at least 100 m past the Level B harassment zone or pre-
clearance zone (whichever is larger) and on a path away from the zone.
A similar pre-pile driving clearance zone will be established to the
north of the POA (from Cairn Point to the opposite bank), allowing
whales to leave Knik Arm undisturbed. Similar to the in-bound whale
clearance zone, pile driving may not commence until a whale(s) moves at
least 100 m past the Level B harassment zone or pre-clearance zone
(whichever is larger) and on a path away from the zone. If non-CIBW
whale species are observed within or likely to enter the Level B
harassment zone prior to pile driving, the POA may commence pile
driving but only if those animals are outside the 100 m shutdown zone
and Level B harassment takes have not been exceeded.
If pile installation or removal has commenced, and a CIBW(s) is
observed within or likely to enter the Level B harassment zone, pile
installation or removal will shut down and not re-commence until the
whale has traveled at least 100 m beyond the Level B harassment zone
and is on a path away from such zone or until no CIBW has been observed
in the Level B harassment zone for 30 minutes.
There may be situations where it is not possible to monitor the
entire Level B harassment zone (e.g., during vibratory hammering of two
unattenuated battered piles). In these cases, the pre-clearance zone
remains applicable.
If during installation and removal of piles, PSOs can no longer
effectively monitor the entirety of the CIBW Level B harassment zone
due to environmental conditions (e.g., fog, rain, wind), pile driving
may continue only until the current segment of pile is driven; no
additional sections of pile or additional piles may be driven until
conditions improve such that the Level B harassment zone can be
effectively monitored. If the Level B harassment zone cannot be
monitored for more than 15 minutes, the entire Level B harassment zone
will be cleared again for 30 minutes prior to pile driving.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> 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
[[Page 31897]]
action; or (4) biological or behavioral context of exposure (e.g., age,
calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
The POA will implement a marine mammal monitoring and mitigation
strategy intended to avoid and minimize impacts to marine mammals (see
Appendix A in the POA's application). The marine mammal monitoring and
mitigation program that is planned for SFD construction will be modeled
after the stipulations outlined in the Final IHAs for Phase 1 and Phase
2 PCT construction (85 FR 19294). The POA will collect electronic data
on marine mammal sightings and any behavioral responses to in-water
pile installation or removal for species observed during pile
installation and removal associated with the SFD Project. Four PSO
teams will work concurrently to provide full coverage for marine mammal
monitoring in rotating shifts during in-water pile installation and
removal. All PSOs will be trained in marine mammal identification and
behaviors. NMFS will review submitted PSO CVs and indicate approval as
warranted.
All PSOs will also undergo project-specific training, which will
include training in monitoring, data collection, theodolite operation,
and mitigation procedures specific to the SFD Project. This training
will also include site-specific health and safety procedures,
communication protocols, and supplemental training in marine mammal
identification and data collection specific to the SFD Project.
Training will include hands-on use of required field equipment to
ensure that all equipment is working and PSOs know how to use the
equipment.
The POA proposes that eleven PSOs will be distributed at four
stations: Anchorage Downtown Viewpoint near Point Woronzof, the
Anchorage Public Boat Dock at Ship Creek, the SFD Project site, and the
north end of POA property. These locations were chosen to maximize CIBW
detection outside of Knik Arm and the mouth of Knik Arm. Specifically,
PSOs at Port Woronzof will have unencumbered views of the entrance to
Knik Arm and can provide information on CIBW group dynamics (e.g.,
group size, demographics, etc.) and behavior of animals approaching
Knik Arm in the absence of and during pile driving. During the time
since the POA submitted their final application, observers for the 2020
PCT Phase 1 project have recommended, and NMFS has included in the
proposed IHA, that the Ship Creek station be moved about 40 m to the
end of the promontory to enhance visibility to the north, especially
near Cairn point. The POA also considered moving a station from the POA
property to Port MacKenzie for an improved view of CIBWs moving from
north to south within Knik Arm. However, Port MacKenzie is not an
available option due to logistical reasons; therefore, the northern
station will remain located on POA property.
Each of the PSO stations will be outfitted with a cargo container
with an observation platform constructed on top. This additional
elevation provides better viewing conditions for seeing distant marine
mammals than from ground level and provides the PSOs with protection
from weather. At least two PSOs will be on watch at any given time at
each station; one PSO will be observing, one PSO will be recording data
(and observing when there are no data to record). The station at the
SFD site will have at least two PSOs. The northern and southern
observations stations will have PSOs who will work in three- to four-
person teams. Teams of three will include one PSO who will be
observing, one PSO who will be recording data (and observing when there
are no data to record), and one PSO who will be resting. When
available, a fourth PSO will assist with scanning, increasing scan
intensity and the likelihood of detecting marine mammals. PSOs will
work on a 60 minute rotation cycle and may observe for no more than 4
hours at time and no more than 12 hours per day. In addition, if POA is
conducting non-PCT-related in-water work that includes PSOs, the PCT
PSOs must be in real-time contact with those PSOs, and both sets of
PSOs must share all information regarding marine mammal sightings with
each other.
Trained PSOs will have no other construction-related tasks or
responsibilities while conducting monitoring for marine mammals.
Observations will be carried out using combinations of equipment that
include 7 by 50 binoculars, 20x/40x tripod mounted binoculars, 25 by
150 ``big eye'' tripod mounted binoculars (North End, Ship Creek, and
Woronzof), and theodolites. PSOs will be responsible for monitoring the
100 m shutdown zone, the Level A harassment zones, the Level B
harassment zones, and the pre-clearance zones, as well as effectively
documenting Level A and Level B harassment take. They will also (1)
report on the frequency at which marine mammals are present in the
project area, (2) report on behavior and group composition near the
POA, (3) record all construction activities, and (4) report on 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 and removal associated with the SFD Project.
Once pile installation and removal are completed for the day, marine
mammal observations will continue for 30 minutes. Observers will work
in collaboration with the POA to immediately communicate the presence
of marine mammals prior to or during pile installation or removal.
A draft report, including all electronic data collected and
summarized from all monitoring locations, must be submitted to NMFS'
MMPA program within 90 days of the completion of monitoring efforts.
The report must include: Dates and times (begin and end) of all marine
mammal monitoring; a description of daily construction activities,
weather parameters and water conditions during each monitoring period;
number of marine mammals observed, by species, distances and bearings
of each marine mammal observed to the pile being driven or removed, age
and sex class, if possible; number of individuals of each species
(differentiated by month as appropriate) detected within the Level A
harassment zones, the Level B harassment zones, and the shutdown zones,
and estimates of number of marine mammals taken, by species (a
correction factor may be applied); description of mitigation
implemented, and description of attempts to distinguish between the
number of individual animals taken and the number of incidences of
take. A final marine mammal monitoring report will be prepared and
submitted to NMFS within 30 days following receipt of comments on the
draft report from NMFS.
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
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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 m
[…truncated; see source link]Indexed from Federal Register on June 15, 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.