Notice2023-08186
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Skagway Ore Terminal Redevelopment Project in Skagway, 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
April 18, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the Municipality of Skagway (MOS) for authorization to take marine mammals incidental to the Ore Terminal redevelopment in Skagway, 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, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in the Request for Public Comments section at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 74 (Tuesday, April 18, 2023)</title>
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[Federal Register Volume 88, Number 74 (Tuesday, April 18, 2023)]
[Notices]
[Pages 23627-23645]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-08186]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC395]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Skagway Ore Terminal
Redevelopment Project in Skagway, 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 Municipality of Skagway
(MOS) for authorization to take marine mammals incidental to the Ore
Terminal redevelopment in Skagway, 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, 1-year renewal that
could be issued under certain circumstances and if all requirements are
met, as described in the Request for Public Comments section at the end
of this notice. NMFS will consider public comments prior to making any
final decision on the issuance of the requested MMPA authorization and
agency responses will be summarized in the final notice of our
decision.
DATES: Comments and information must be received no later than May 18,
2023.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#eba2bfbbc5838a99878a88838e99ab85848a8ac58c849d"><span class="__cf_email__" data-cfemail="da938e8af4b2bba8b6bbb9b2bfa89ab4b5bbbbf4bdb5ac">[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: Jenna Harlacher, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</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 proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is 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.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review. We
will review all comments submitted in response to this notice prior to
concluding our NEPA process or making a final decision on the IHA
request.
[[Page 23628]]
Summary of Request
On August 9, 2022, NMFS received a request from MOS for an IHA to
take marine mammals incidental to Ore Terminal redevelopment in
Skagway, Alaska. Following NMFS' review of the application and
subsequent revised versions, MOS submitted a final application that was
deemed adequate and complete on February 23, 2023. MOS's request is for
take of 7 species (including 11 stocks) by Level B and Level A
harassment. Neither MOS nor NMFS expect serious injury or mortality to
result from this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
MOS proposes to redevelop the Skagway Ore Terminal in Skagway,
Alaska. The proposed project will cover construction from fall 2023
through spring 2024 to avoid construction during cruise ship season. A
maximum of 152 days of pile installation and removal activity will
occur, with some days including both impact and vibratory pile driving.
This project involves installation and removal of 36 temporary steel
pile guides, removal of 692 piles, and installation of 244 permanent
steel piles. Two different installation methods will be used including
vibratory pile driving and impact pile driving. Sounds resulting from
pile installation and removal may result in the incidental take of
marine mammals by Level A and Level B harassment in the form of
auditory injury or behavioral harassment.
Dates and Duration
The proposed IHA would be effective from November 2023 through
March 2024. The total expected work duration would be a max of 152 days
with some days including both impact and vibratory pile driving (a
total of 134 days of vibratory pile installation and 77 days of impact
pile driving). This estimate is the maximum days of activity possible
and is a conservative estimate that includes any potential delays.
Because of the short construction season and limited winter daylight
hours, construction would occur during both daylight hours and for a
short time after sunset, with construction lighting.
Specific Geographic Region
The proposed activity will occur in Skagway, Alaska, within the
Skagway Ore Basin (Figure 1). Skagway is the northernmost city in
Southeast Alaska. The MOS is at the southwestern end of the 2.5-mile (4
kilometer) long Skagway River valley, which empties into Taiya inlet at
the head of Lynn Canal. The Ore Terminal is a deep-water port that
transitions sharply from a limited nearshore area into deep marine
waters of Lynn Canal. The Ore Terminal basin area has nearly uniform
depth of approximately 40 feet (12.2 meters) lower low water.
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TN18AP23.032
BILLING CODE 3510-22-C
[[Page 23629]]
Detailed Description of Specific Activity
The proposed project will remove 269 steel and 423 creosote-treated
timber piles from the existing Ore dock in Skagway Harbor. These piles
will be removed using the vibratory hammer or directly pulled using a
clamshell bucket. MOS proposes to install and remove 36 temporary steel
piles using vibratory hammers; these piles will be removed by vibratory
means by the end of construction. The temporary piles will act as
supports or reaction frames to facilitate the installation of permanent
piling. Steel permanent piles (248) will be installed to support the
new dock structures, as part of the mooring dolphins, and as fender
piles. Piles will be driven to the maximum depth feasible using a
vibratory pile driver and partially driven and proofed using an impact
pile driver to reach required depths. The piles would be installed
using both methods over 152 days (Table 1).
Additional actions occurring under the proposed action that are not
anticipated to generate in-water noise resulting in marine mammal
harassment include vessel movements to support construction and out of
water dock components. NMFS does not expect that these ancillary
activities will harm or harass marine mammals and no incidental takes
are expected as a result of these activities. Therefore, these
activities are not discussed further in this document.
Table 1--Pile Installation Methods and Durations
----------------------------------------------------------------------------------------------------------------
Number of Piles drive/ Estimated
Pile size, method piles Duration/strikes per pile day days
----------------------------------------------------------------------------------------------------------------
36-in steel pile **, Impact Installation. 78 1800 strikes............... 2 39
24-in steel pile, Impact Installation.... 170 700 strikes................ 5 38
30-in steel pile *, Vibratory 439 45 min..................... 5 95
Installation and Removal.
36-in steel pile **, Vibratory 74 45 min..................... 5 15
Installation.
14-in timber pile, Vibratory Removal..... 423 21 min..................... 18 24
----------------------------------------------------------------------------------------------------------------
* Includes piles sizes: 10.75-in, 14-in, 16-in, 20-in, 24-in, 28-in, and 30-in.
** Includes pile sizes: 36-in, 42-in, and 48-in.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, referenced here, instead of reprinting the
information. Additional information regarding population trends and
threats may be found in NMFS' Stock Assessment Reports (SARs;
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">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'
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, 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. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is expected to occur, PBR
and annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species or
stocks 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 stocks managed under the MMPA in this region
are assessed in NMFS' 2021 Alaska Marine Mammal SARs. All values
presented in Table 2 are the most recent available at the time of
publication (including from the draft 2022 SARs) and are available
online at: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 2--Species Likely Impacted by the Specified Activities
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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 novaeanglinae Central North Pacific -,D,Y 10,103 (0.3, 7,890, 83 26
Stock. 2006).
Minke whale..................... Balaenoptera Alaska................. -,-,N UNK................... NA 0
acutorostra.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer whale.................... Orca orcinus........... Eastern North Pacific, -,-,N 302 (N/A, 302, 2018).. 2.2 0.2
Norther Residents,
Southeast Alaska.
[[Page 23630]]
Eastern North Pacific -,-,N 1,920 (N/A, 1,920, 19 1.3
Alaska Residents. 2019).
West Coast Transients.. -,-,N 349 (N/A, 349, 2018).. 3.5 0.4
Gulf, Aleutian, Bering -,-,N 587 (N/A, 587, 2020).. 5.9 0.8
Transients.
Family Phocoenidae (porpoises):
Harbor Porpoise................. Phocoena phocoena...... Southeast Alaska....... -,-,N 1,057 (N/A,1,057, ......... 34
2019).
Dall's porpoise \4\............. Phocoenoides dalli..... Alaska................. -,-,N 15,432 (0.28, 13, 110, 131 37
2021).
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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 Stock.......... E,D,Y 52,932 (N/A, 52,932, 318 254
2019).
Eastern Stock.......... -,-,N 43,201 (N/A, 43,201, 2,592 112
2017).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vituline Alaska--Lynn Canal/ -,-,N 13,388 (N/A, 11,867, 214 50
richardii. Stephens Passage. 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Previous abundance estimates covering the entire stock's range are no longer considered reliable and the current estimates presented in the SARs and
reported here only cover a portion of the stock's range. Therefore, the calculated Nmin and PBR is based on the 2015 survey of only a small portion of
the stock's range. PBR is considered to be biased low since it is based on the whole stock whereas the estimate of mortality and serious injury is for
the entire stock's range.
On January 24, 2023, NMFS published the draft 2022 SARs (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>-region). The Alaska and Pacific Ocean SARs
include a proposed update to the humpback whale stock structure and the
Alaska SAR includes a proposed update to the Southeast Alaska harbor
porpoise stock structure. These new structures, if finalized, would
modify the MMPA-designated humpback stocks to align more closely with
the ESA-designated Distinct Population Segments (DPSs), and for harbor
porpoise to align with genetics, trends in abundance, and discontinuous
distribution that supports the delineation of two demographically
independent populations. Please refer to the draft 2022 Alaska and
Pacific Ocean SARs for additional information.
NMFS Office of Protected Resources, Permits and Conservation
Division has generally considered peer-reviewed data in draft SARs
(relative to data provided in the most recent final SARs), when
available, as the best available science, and has done so here for all
species and stocks, with the exception of a new proposal to revise
humpback whale and harbor porpoise stock structure. Given that the
proposed changes to the stock structures involve application of NMFS's
Guidance for Assessing Marine Mammals Stocks and could be revised
following consideration of public comments, it is more appropriate to
conduct our analysis in this proposed authorization based on the status
quo stock structure identified in the most recent final SARs (2021;
Carretta et al., 2022; Muto et al., 2022).
As indicated above, all 7 species (with 11 managed stocks) in Table
2 temporally and spatially co-occur with the activity to the degree
that take is reasonably likely to occur, and for which we have proposed
authorization. In addition to what is included in Sections 3 and 4 of
the application, the SARs, and NMFS' website, further localized data
and detail informing the baseline for select species (i.e., information
regarding current Unusual Mortality Events (UME) and important habitat
areas) is provided below.
A previous monitoring report from the White Pass & Yukon Route
Railroad Dock Dolphin Installation project includes local marine mammal
sighting data from Skagway. From their 57-day (March-May) protected
species monitoring, no minke whale, harbor porpoise, or Dall's porpoise
were sighted near the project area in Skagway. Twenty-six killer whales
were sighted on 4 days, including 2 sightings in March and the rest in
April. Killer whales were observed traveling, diving and swimming, and
were observed greater than 300 m from the project site. Additionally,
735 harbor seals were observed on 46 days of in-water activity, with
sightings occurring in all months of the project. The majority of the
harbor seal observations were near Yakutania Point, a harbor seal
haulout site. Most of the sightings occurred at least 1,000 m from the
project site, however harbor seals came as close as 150 m and as far as
5,000 m. Harbor seals were observed travelling, swimming, playing,
milling, looking, hauled out, sinking, and feeding (Owl Ridge Natural
Resource Consultants, 2019).
Humpback Whale
Prior to 2016, humpback whales were listed under the ESA as an
endangered species worldwide. Following a 2015 global status review
(Bettridge et al., 2015), NMFS established 14 Distinct Population
Segments (DPS) with different listing statuses (81 FR 62259, September
8, 2016) pursuant to the ESA.
There are two MMPA stocks of humpback whales in the North Pacific
in NMFS Alaska Marine Mammal SAR. Humpback whales from the Western
North Pacific stock are not likely to be observed in Southeast Alaska
and are
[[Page 23631]]
not expected in the project area. Individuals from the Central North
Pacific stock of humpback whales are found in Southeast Alaska and have
the potential to be in the project vicinity.
Because DPSs do not overlap exactly with the existing MMPA stocks,
there is the possibility that either the Hawaii DPS or the Mexico DPS
could be in the project area (Muto et al., 2020). Although NMFS has
determined that humpback whales in Southeast Alaska have a 98 percent
probability of being from the Hawaii DPS (Wade et al., 2016), there is
a 2 percent likelihood that a humpback whale from the Mexico DPS, which
is threatened under the ESA, could be in the project area. No critical
habitat has been designated for the humpback whale in the vicinity of
the Project.
Southeast Alaska primarily provides summer feeding grounds for
humpback whales that typically arrive in Southeast Alaska between March
and November, although they could be present in Southeast Alaska year-
round. Lynn Canal is within the North Pacific feeding and wintering
area, and is a biologically import feeding ground for humpback whales
(active June-August). However, these areas are outside of Taiya inlet
and during months when the activity is not occurring.
Local observers in Taiya Inlet have historically reported humpback
whales; however, no scientific surveys have documented the species in
the area (Dahlheim et al., 2009). During the White Pass & Yukon Route
Railroad Dock Dolphin Installation project, humpback whales were
sighted in Taiya Inlet twice in early May. These sightings occurred 3-4
km from the project site and were observed travelling (Owl Ridge
Natural Resource Consultants, 2019). Group sizes are largest in summer
and fall, increasing over the course of the year and peaking in late
August and September (Dalheim et al., 2009). The Central North Pacific
stock is increasing at rates of up to approximately 7 percent per year
(ADFG, 2008; Calambokidis et al., 2008).
Steller Sea Lion
Steller sea lions were listed as threatened range-wide under the
ESA on November 26, 1990 (55 FR 49204). Steller sea lions were
subsequently partitioned into the western and eastern DPSs in 1997 (62
FR 24345, May 5, 1997). The eastern DPS remained classified as
threatened until it was delisted in November 2013. The western DPS
(those individuals west of the 144[deg] W longitude or Cape Suckling,
Alaska) was upgraded to endangered status following separation of the
DPSs; it remains endangered today and considered a strategic stock
under the MMPA. Both stocks of Steller sea lions are found in Southeast
Alaska and have the potential to occur in the project area, however it
is more likely they would be from the Eastern stock.
Critical habitat for Steller sea lions was designated by NMFS in
1993 based on the following essential physical and biological habitat
features: terrestrial habitat (including rookeries and haulouts
important for rest, reproduction, growth, social interactions) and
aquatic habitat (including nearshore waters around rookeries and
haulouts, free passage for migration, prey resources, and foraging
habitats) (58 FR 45269).
During the White Pass & Yukon Route Railroad Dock Dolphin
Installation project, Steller sea lions were sighted on 27 separate
days with 165 individuals. Majority of the sightings occurred during
April and May, with only six individuals sighted in March. Although a
few sightings were 500 meters from pile driving activities, most
sightings were recorded over 1,000 meters away from the pile driving
site. Sightings were of single individuals and rafts up to 25
individuals. Steller sea lions were observed swimming, traveling,
resting, porpoising, looking, sinking, and milling (Owl Ridge Natural
Resource Consultants, 2019).
Gran Point is the closest major haulout and designated critical
habitat area, approximately 24 miles (38.6 kilometers) from the Project
site and outside of Taiya Inlet (NOAA, 2022b). Additionally, there is a
nearby Steller sea lion haulout at the southern tip of Taiya Inlet
utilized by Steller sea lions during the Eulachon run. The Lutak Inlet
Eulachon run between April and May correlates with higher sea lion
numbers near the Project site, with the Taiya Point haulout
(approximately 10 miles (16.1 kilometers) away) being a popular land
site (NOAA, 2022b). However, the Eulachon run is outside of the project
work window.
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. 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, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). 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 (dolphins, 150 Hz to 160 kHz.
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) (true 50 Hz to 86 kHz.
seals).
[[Page 23632]]
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
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.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which 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 whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activity
can occur from impact and vibratory pile driving and removal. The
effects of underwater noise from MOS's proposed activities have the
potential to result in Level A or Level B harassment of marine mammals
in the action area.
Description of Sound Source
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far. The sound level of an area is defined by the
total acoustical energy being generated by known and unknown sources.
These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include vibratory pile removal, and impact and vibratory pile driving.
The sounds produced by these activities fall into one of two general
sound types: impulsive and non-impulsive. Impulsive sounds (e.g.,
explosions, gunshots, sonic booms, impact pile driving) are typically
transient, brief (less than 1 second), broadband, and consist of high
peak sound pressure with rapid rise time and rapid decay (ANSI, 1986;
NIOSH, 1998; ANSI, 2005; NMFS, 2018a). Non-impulsive sounds (e.g.
aircraft, machinery operations such as drilling or dredging, vibratory
pile driving, and active sonar systems) can be broadband, narrowband or
tonal, brief or prolonged (continuous or intermittent), and typically
do not have the high peak sound pressure with raid rise/decay time that
impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018a). The
distinction between these two sound types is important because they
have differing potential to cause physical effects, particularly with
regard to hearing (e.g., Ward 1997 in Southall et al., 2007).
Two types of hammers would be used on this project: impact and
vibratory. Impact hammers operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the weight of the hammer to push them into the sediment. Vibratory
hammers produce significantly less sound than impact hammers. Peak
sound pressure levels (SPLs) may be 180 dB or greater, but are
generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009). Rise time is
slower, reducing the probability and severity of injury, and sound
energy is distributed over a greater amount of time (Nedwell and
Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of MOS's proposed activity on marine
mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of equipment and personnel; however, any impacts to marine
mammals are expected to be primarily acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
driving.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving is the primary means by which marine
mammals may be harassed from the MOS's specified activity. In general,
animals exposed to natural or anthropogenic sound may experience
physical and psychological effects, ranging in magnitude from none to
severe (Southall et al., 2007). In
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general, exposure to pile driving noise has the potential to result in
auditory threshold shifts and behavioral reactions (e.g., avoidance,
temporary cessation of foraging and vocalizing, changes in dive
behavior). Exposure to anthropogenic noise can also lead to non-
observable physiological responses, such as an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection. The effects of pile
driving noise on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mom
with calf), duration of exposure, the distance between the pile and the
animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2004; Southall et al., 2007).
Here we discuss physical auditory effects (threshold shifts) followed
by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of TS
is customarily expressed in decibels (dB). A TS can be permanent or
temporary. As described in NMFS (2018), there are numerous factors to
consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how an animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB
threshold shift approximates PTS onset (see Ward et al., 1958, 1959;
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996;
Henderson et al., 2008). PTS levels for marine mammals are estimates,
as with the exception of a single study unintentionally inducing PTS in
a harbor seal (Kastak et al., 2008), there are no empirical data
measuring PTS in marine mammals largely due to the fact that, for
various ethical reasons, experiments involving anthropogenic noise
exposure at levels inducing PTS are not typically pursued or authorized
(NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum threshold shift clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in
Finneran (2015), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum, the amount of
TTS is typically small and the growth curves have shallow slopes. At
exposures with higher SELcum, the growth curves become steeper and
approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in 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 a 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.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
For cetaceans, published data on the onset of TTS are limited to the
captive bottlenose dolphin (Tursiops truncatus), beluga whale
(Delphinapterus leucas), harbor porpoise, and Yangtze finless porpoise
(Neophocoena asiaeorientalis), and for pinnipeds in water, measurements
of TTS are limited to harbor seals, elephant seals (Mirounga
angustirostris), and California sea lions (Zalophus californianus).
These studies examine hearing thresholds measured in marine mammals
before and after exposure to intense sounds. The difference between the
pre-exposure and post-exposure thresholds can be used to determine the
amount of threshold shift at various post-exposure times. The amount
and onset of TTS depends on the exposure frequency. Sounds at low
frequencies, well below the region of best sensitivity, are less
hazardous than those at higher frequencies, near the region of best
sensitivity (Finneran and Schlundt, 2013). At low frequencies, onset-
TTS exposure levels are higher compared to those in the region of best
sensitivity (i.e., a low frequency noise would need to be louder to
cause TTS onset when TTS exposure level is higher), as shown for harbor
porpoises and harbor seals (Kastelein et al., 2019a, 2019b, 2020a,
2020b). In addition, TTS can accumulate across multiple exposures, but
the resulting TTS will be less than the TTS from a single, continuous
exposure with the same SEL (Finneran et al., 2010; Kastelein et al.,
2014; Kastelein et al., 2015a; Mooney et al., 2009). This means that
TTS predictions based on the total, cumulative SEL will overestimate
the amount of TTS from intermittent exposures, such as sonars and
impulsive sources. Nachtigall et al. (2018) and Finneran (2018)
describe the measurements of hearing sensitivity of multiple odontocete
species (bottlenose dolphin, harbor porpoise, beluga, and false killer
whale (Pseudorca crassidens)) when a relatively loud sound was preceded
by a warning sound. These captive animals were shown to reduce hearing
sensitivity when warned of an impending intense sound. Based on these
experimental observations of captive animals, the authors suggest that
wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that
echolocating animals (including odontocetes) might have anatomical
specializations that might allow for
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conditioned hearing reduction and filtering of low-frequency ambient
noise, including increased stiffness and control of middle ear
structures and placement of inner ear structures (Ketten et al., 2021).
Data available on noise-induced hearing loss for mysticetes are
currently lacking (NMFS, 2018).
Behavioral Harassment--Exposure to noise from pile driving and
removal also has the potential to behaviorally disturb marine mammals.
Available studies show wide variation in response to underwater sound;
therefore, it is difficult to predict specifically how any given sound
in a particular instance might affect marine mammals perceiving the
signal. If a marine mammal does react briefly to an underwater sound by
changing its behavior or moving a small distance, the impacts of the
change are unlikely to be significant to the individual, let alone the
stock or population. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on individuals and populations could be significant
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); and, avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al.,
2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can
vary not only among individuals but also within an individual,
depending on previous experience with a sound source, context, and
numerous other factors (Ellison et al., 2012), and can vary depending
on characteristics associated with the sound source (e.g., whether it
is moving or stationary, number of sources, distance from the source).
In general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans. Please see Appendices B-C of Southall et
al., (2007) for a review of studies involving marine mammal behavioral
responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
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) and, more rarely, studied in wild populations
(e.g., 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), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar projects in the area.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation) (Richardson et al., 1995). Masking occurs when
the receipt of a sound is interfered with by another coincident sound
at similar frequencies and at similar or higher intensity, and may
occur whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a
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noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions. Masking of
natural sounds can result when human activities produce high levels of
background sound at frequencies important to marine mammals.
Conversely, if the background level of underwater sound is high (e.g.,
on a day with strong wind and high waves), an anthropogenic sound
source would not be detectable as far away as would be possible under
quieter conditions and would itself be masked.
Airborne Acoustic Effects--Although pinnipeds are known to haul out
regularly near Skagway and Taiya Inlet, we believe that incidents of
take resulting solely from airborne sound are unlikely due to the
sheltered proximity between the proposed project area and these haulout
sites (Taiya point, Gran Point, Yakutania Point, and in Taiya Inlet).
There is a possibility that an animal could surface in-water, but with
head out, within the area in which airborne sound exceeds relevant
thresholds and thereby be exposed to levels of airborne sound that we
associate with harassment, but any such occurrence would likely be
accounted for in our estimation of incidental take from underwater
sound. Therefore, authorization of incidental take resulting from
airborne sound for pinnipeds is not warranted, and airborne sound is
not discussed further here. Cetaceans are not expected to be exposed to
airborne sounds that would result in harassment as defined under the
MMPA.
Marine Mammal Habitat Effects
The MOS's construction activities could have localized, temporary
impacts on marine mammal habitat and their prey by increasing in-water
sound pressure levels and slightly decreasing water quality. However,
the proposed location is not heavily used by marine mammals and is in
close proximity to a heavily trafficked industrial area. Construction
activities are of short duration and would likely have temporary
impacts on marine mammal habitat through increases in underwater and
airborne sound. Increased noise levels may affect acoustic habitat (see
Masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project area (see discussion below). During impact
and vibratory pile driving, elevated levels of underwater noise would
ensonify the project area where both fish and mammals occur and could
affect foraging success. Additionally, marine mammals may avoid the
area during construction; however, displacement due to noise is
expected to be temporary and is not expected to result in long-term
effects to the individuals or populations.
Temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the area where piles are
installed or removed. In general, turbidity associated with pile
installation is localized to about a 25-ft (7.6 meter) radius around
the pile (Everitt et al., 1980). The sediments of the project site will
settle out rapidly when disturbed. Cetaceans are not expected to be
close enough to the pile driving areas to experience effects of
turbidity, and any pinnipeds could avoid localized areas of turbidity.
Local strong currents are anticipated to disburse any additional
suspended sediments produced by project activities at moderate to rapid
rates depending on tidal stage. Therefore, we expect the impact from
increased turbidity levels to be discountable to marine mammals and do
not discuss it further.
In-Water Construction Effects on Potential Foraging Habitat
The proposed activities would result in a minor loss of benthic
habitat and potentially change underwater features for fish, but these
changes are insignificant and limited to the area of redevelopment. The
total seafloor area likely impacted by the project is relatively small
compared to the available habitat in Southeast Alaska and does not
include any Biologically Important Areas (BIA) or other habitat of
known importance. The area is highly influenced by anthropogenic
activities. Additionally, the total seafloor area affected by pile
installation and removal is a small area compared to the vast foraging
area available to marine mammals in the area. At best, the impact area
provides marginal foraging habitat for marine mammals and fishes.
Furthermore, pile driving at the project site would not obstruct
movements or migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity.
Effects on Potential Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fish, zooplankton, etc.). Marine mammal prey varies by
species, season, and location. Here, we describe studies regarding the
effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses, such as flight or
avoidance, are the most likely effects. Short duration, sharp sounds
can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
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). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have
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shown no or slight reaction to impulse sounds (e.g., Pena et al., 2013;
Wardle et al., 2001; Jorgenson and Gyselman, 2009; Popper et al.,
2015).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al., (2012a) showed that a TTS of 4-6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual
fish is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fish from pile driving activities at the
project areas would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated.
Construction activities, in the form of increased turbidity, have
the potential to adversely affect forage fish in the project area.
Forage fish form a significant prey base for many marine mammal species
that occur in the project area. Increased turbidity is expected to
occur in the immediate vicinity (on the order of 10 ft (3 m) or less)
of construction activities. However, suspended sediments and
particulates are expected to dissipate quickly within a single tidal
cycle. Given the limited area affected and high tidal dilution rates,
any effects on forage fish are expected to be minor or negligible.
Finally, exposure to turbid waters from construction activities is not
expected to be different from the current exposure; fish and marine
mammals in the Passage Canal are routinely exposed to substantial
levels of suspended sediment from natural and anthropogenic sources.
In summary, given the short-term and limited duration of sound
associated with pile driving events and the relatively small areas
being affected, pile driving activities associated with the proposed
action are not likely to have a permanent adverse effect on any fish
habitat, or populations of fish species. Any behavioral avoidance by
fish of the disturbed area would be temporary and would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity. Additionally, all in-water work will occur during
the winter, when marine resident fish species are only present in
limited numbers. Thus, we conclude that impacts of the specified
activity are not likely to have more than short-term adverse effects on
any prey habitat or populations of prey species. Further, any impacts
to marine mammal habitat are not expected to result in significant or
long-term consequences for individual marine mammals, or to contribute
to adverse impacts on their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., vibratory and impact pile driving) has
the potential to result in disruption of behavioral patterns for
individual marine mammals. There is also some potential for auditory
injury (Level A harassment) to result. The proposed mitigation and
monitoring measures are expected to minimize the severity of the taking
to the extent practicable. As described previously, no serious injury
or mortality is anticipated or proposed to be authorized for this
activity. Below, we describe how the proposed take numbers are
estimated.
For acoustic impacts, 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) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential 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 estimates.
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 permanent threshold shift (PTS) of some
degree (equated to Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources.
MOS's proposed activity includes the use of continuous (vibratory
pile driving) and impulsive (impact pile driving) sources, and
therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are
applicable.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on
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Marine Mammal Hearing (Version 2.0) (Technical Guidance, 2018)
identifies dual criteria to assess auditory injury (Level A harassment)
to five different marine mammal groups (based on hearing sensitivity)
as a result of exposure to noise from two different types of sources
(impulsive or non-impulsive). MOS's proposed activity includes the use
of impulsive (impact pile driving) and non-impulsive (vibratory pile
driving) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">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, American National Standards Institute (ANSI)
defines peak sound pressure 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 are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., impact pile driving and
vibratory pile driving and removal).
In order to calculate distances to the Level A harassment and Level
B harassment thresholds for the methods and piles being used in this
project, NMFS used acoustic monitoring data from other locations to
develop source levels for the various pile types, sizes and methods
(Table 5).
Table 5--Observed Source Levels for Pile Installation and Removal
------------------------------------------------------------------------
Pile size, method SPLs (dB) Source
------------------------------------------------------------------------
36-in to 48-in steel pile**, 193 RMS Caltrans 2020.
Impact Installation.
24-in steel pile, Impact 189 RMS Caltrans 2020.
Installation.
Up to 30-in steel pile*, 159 RMS Caltrans 2020.
Vibratory Installation and
Removal.
36-in steel pile**, Vibratory 170 RMS Caltrans 2015.
Installation.
14-in timber pile, Vibratory 158 RMS Greenbusch 2018.
Removal.
------------------------------------------------------------------------
Note: SPLs = single strike sound pressure level; RMS = root mean square.
* Includes piles sizes: 10.75-in, 14-in, 16-in, 20-in, 24-in, 28-in, and
30-in.
** Includes pile sizes: 36-in, 42-in, and 48-in.
Level B Harassment Zones
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
The recommended TL coefficient for most nearshore environments is
the practical spreading value of 15. This value results in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions, which is the most appropriate
assumption for MOS's proposed activities. The Level B harassment zones
for the proposed activities are shown in Table 6.
Level A Harassment Zones
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources, such as pile installation or
[[Page 23638]]
removal, the optional User Spreadsheet tool predicts the distance at
which, if a marine mammal remained at that distance for the duration of
the activity, it would be expected to incur PTS. The isopleths
generated by the User Spreadsheet used the same TL coefficient as the
Level B harassment zone calculations (i.e., the practical spreading
value of 15). Inputs used in the User Spreadsheet (e.g., number of
piles per day, duration and/or strikes per pile, source levels) are
presented in Table 1 and Table 5. The resulting isopleths are reported
in Table 6.
Table 6--Level A and Level B Harassment Isopleths for Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zone (m) Level B
Activity -------------------------------------------------------------------------------- harassment
LF cetacean MF cetacean HF cetacean Phocids Otariids zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in to 48-in steel pile **, Impact Installation....... 2,345.7 83.4 2,794.1 1255.3 91.4 1,584.9
24-in steel pile, Impact Installation................... 1,245.8 44.3 1,483.9 666.7 48.5 857.7
Up to 30-in steel pile *, Vibratory Installation and 12.1 1.1 17.9 7.4 0.5 3,981
Removal................................................
36-in steel pile **, Vibratory Installation............. 65.6 5.8 97 39.9 2.8 21,544
14-in timber pile, Vibratory Removal.................... 14.7 1.3 21.7 8.9 0.6 3,414.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Includes piles sizes: 10.75-in, 14-in, 16-in, 20-in, 24-in, 28-in, and 30-in.
** Includes pile sizes: 36-in, 42-in, and 48-in.
Marine Mammal Occurrence
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations.
For marine mammal density information in the Skagway area we use
data from the Pacific Navy Marine Species Density Database (U.S. Navy,
2021) and sources specific to the Skagway area to estimate take for
marine mammals. The Marine Species Density Database incorporates
analyzed literature and research for marine mammal density estimates
per season for the Gulf of Alaska and the Western Behm Canal. The
Western Behm Canal is closer to the Project site and geographically
more similar (an inlet compared to open ocean); therefore, density
estimates for Western Behm Canal are used as proxies. Density estimates
specific to Taiya Inlet or Lynn Canal are not available for any of the
species addressed in this application, and therefore takes must be
estimated based on the nearest available and most appropriate density
estimates, plus site-specific knowledge and professional judgement.
Table 7 density estimates are calculated based on the in-water work
window (November-March) and based on winter density estimates of
Western Behm Canal.
Table 7--Density of Marine Mammal Species in the Project Area
------------------------------------------------------------------------
Density (per
Species km \2\)
------------------------------------------------------------------------
Humpback whale.......................................... 0.0081
Minke Whale............................................. 0.0017
Dall's Porpoise......................................... 0.1210
Harbor Porpoise......................................... 0.4547
Killer Whale............................................ 0.0041
Harbor Seal............................................. 1.730
Steller Sea Lion........................................ 0.0122
------------------------------------------------------------------------
Take Estimation
Here, we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
Using the overall area of disturbance generated by pile removal and
installation given calculated distances to attenuation below
disturbance (Level B harassment) thresholds, incidental take for each
activity is estimated by the following equation:
Incidental take estimate = species density * ensonified area* days of
pile-related activity
Due to little observational data available for marine mammals in
Taiya Inlet and Lynn Canal in the winter, this equation is a reasonable
extrapolation for take estimates, which relies on the likelihood that a
species is present within the ensonified area on a day where the
proposed activity is occurring. The estimation of take by Level A
harassment is based on the likelihood that marine mammals would enter
the Level A harassment zone without detection.
Table 8--Proposed Authorized Amount of Taking and Percent of Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Take by Level Take by Level Percent of
Species Stock/DPS A harassment B harassment Total take stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale................................. Hawaii DPS + Mexico DPS................ 2 14 16 <1
Minke Whale.................................... Alaska................................. 2 6 8 \1\ NA
Dall's Porpoise................................ Alaska................................. 10 173 183 1.4
Harbor Porpoise................................ Southeast Alaska....................... 5 69 74 7
Killer Whale................................... Eastern North Pacific, Northern 2 90 92 2.91
Residents, Southeast Alaska + Eastern
North Pacific, Alaska Residents + West
Coast Transients + Gulf, Aleutian,
Bering Transients.
Harbor Seal.................................... Alaska--Lynn Canal/Stephens Passage.... 203 2,451 2,654 19.9
Steller Sea Lion............................... Eastern US + Western US................ 2 211 213 <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Alaska SAR does not have an estimated population size for the Alaska stock of minke whales due only a portion of the stock's range being surveyed
and such few whales seen during stock abundance surveys.
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,
[[Page 23639]]
and areas of similar significance, and on the availability of the
species or stock for taking for certain subsistence uses. 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, NMFS
considers 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, as
well as subsistence uses. 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 MOS implementation,
which may consider such things as cost and impact on operations.
NMFS proposed the following mitigation measures be implemented for
MOS's pile installation and removal activities.
Mitigation Measures
MOS must follow mitigation measures as specified below:
<bullet> Ensure that construction supervisors and crews, the
monitoring team, and relevant MOS staff are trained prior to the start
of all pile driving activity, so that responsibilities, communication
procedures, monitoring protocols, and operational procedures are
clearly understood. New personnel joining during the project must be
trained prior to commencing work;
<bullet> Employ Protected Species Observers (PSOs) and establish
monitoring locations as described in the application and the IHA. MOS
must monitor the project area to the maximum extent possible based on
the required number of PSOs, required monitoring locations, and
environmental conditions. For all pile driving and removal, at least
one PSO must be used. The PSO will be stationed as close to the
activity as possible;
<bullet> The placement of the PSOs during all pile driving and
removal activities will ensure that the entire shutdown zone is visible
during pile driving activities. Should environmental conditions
deteriorate such that marine mammals within the entire shutdown zone
will not be visible (e.g., fog, heavy rain), pile driving and removal
must be delayed until the PSO is confident marine mammals within the
shutdown zone could be detected;
<bullet> Monitoring must take place from 30 minutes prior to
initiation of pile driving activity (i.e., pre-clearance monitoring)
through 30 minutes post-completion of pile driving activity;
<bullet> Pre-start clearance monitoring must be conducted during
periods of visibility sufficient for the lead PSO to determine that the
shutdown zones indicated in Table 9 are clear of marine mammals. Pile
driving may commence following 30 minutes of observation when the
determination is made that the shutdown zones are clear of marine
mammals;
<bullet> MOS 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 30-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
30 minutes or longer;
<bullet> If a marine mammal is observed entering or within the
shutdown zones indicated in Table 9, pile driving must be delayed or
halted. If pile driving is delayed or halted due to the presence of a
marine mammal, the activity may not commence or resume until either the
animal has voluntarily exited and been visually confirmed beyond the
shutdown zone (Table 9) or 15 minutes have passed without re-detection
of the animal; and
<bullet> As proposed by MOS, in water activities will take place
only between civil dawn and civil dusk and for a limited duration after
dusk with lighting when PSOs can effectively monitor for the presence
of marine mammals; during conditions with a Beaufort Sea State of 4 or
less; when the entire shutdown zone and adjacent waters are visible
(e.g., monitoring effectiveness in not reduced due to rain, fog, snow,
etc.).
Shutdown Zones
MOS will establish shutdown zones for all pile driving activities.
The purpose of a shutdown zone is generally to define an area within
which shutdown of the activity would occur upon sighting of a marine
mammal (or in anticipation of an animal entering the defined area).
Shutdown zones would be based upon the Level A harassment zone for each
pile size/type and driving method where applicable, as shown in Table
9.
For in-water heavy machinery activities other than pile driving, if
a marine mammal comes within 10 m, work generating underwater noise
will stop and vessels will reduce speed to the minimum level required
to maintain steerage and safe working conditions. A 10 m shutdown zone
would also serve to protect marine mammals from physical interactions
with project vessels during pile driving and other construction
activities, such as barge positioning or drilling. If an activity is
delayed or halted due to the presence of a marine mammal, the activity
may not commence or resume until either the animal has voluntarily
exited and been visually confirmed beyond the shutdown zone indicated
in Table 9 or 15 minutes have passed without re-detection of the
animal. Construction activities must be halted upon observation of a
species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met entering or within the harassment zone.
All marine mammals will be monitored in the Level B harassment
zones and throughout the area as far as visual monitoring can take
place. If a marine mammal enters the Level B harassment zone, in-water
activities will continue and the animal's presence within the estimated
harassment zone will be documented.
MOS would also establish shutdown zones for all marine mammals for
which take has not been authorized or for which incidental take has
been authorized but the authorized number of takes has been met. These
zones are equivalent to the Level B harassment zones for each activity.
If a marine mammal species not covered under this IHA enters the
shutdown zone, all in-water activities will cease until the animal
leaves the zone or has not been observed for at least 15 minutes, and
NMFS will be notified about species and precautions taken. Pile driving
will proceed if the non-IHA species is observed to leave the Level B
harassment zone or if 15 minutes have passed since the last
observation.
If shutdown and/or clearance procedures would result in an imminent
safety concern, as determined by MOS or its designated officials, the
in-water
[[Page 23640]]
activity will be allowed to continue until the safety concern has been
addressed, and the animal will be continuously monitored.
Table 9--Proposed Shutdown Zones and Monitoring Zones
----------------------------------------------------------------------------------------------------------------
Activity Minimum shutdown zone
----------------------------------------------------------------------------------------------------
Low- Mid- High- Harassment
frequency frequency frequency zone
(LF) (MF) (HF) Phocid Otariid
cetaceans cetaceans cetaceans
----------------------------------------------------------------------------------------------------------------
36-in to 48-in steel pile **, 2,350 85 2,795 1,260 95 1,585
Impact Installation..............
24-in steel pile, Impact 1,250 45 1,485 670 50 860
Installation.....................
Up to 30-in steel pile *, 15 10 20 10 10 3,985
Vibratory Installation and
Removal..........................
36-in steel pile **, Vibratory 70 10 100 40 10 21,545
Installation.....................
14-in timber pile, Vibratory 15 10 25 10 10 3,415
Removal..........................
----------------------------------------------------------------------------------------------------------------
* Includes piles sizes: 10.75-in, 14-in, 16-in, 20-in, 24-in, 28-in, and 30-in.
** Includes pile sizes: 36-in, 42-in, and 48-in.
Protected Species Observers
The placement of PSOs during all construction activities (described
in the Proposed Monitoring and Reporting section) would ensure that the
entire shutdown zone is visible. Should environmental conditions
deteriorate such that the entire shutdown zone would not be visible
(e.g., fog, heavy rain), pile driving would be delayed until the PSO is
confident marine mammals within the shutdown zone could be detected.
PSOs would monitor the full shutdown zones and the remaining Level
A harassment and the Level B harassment zones to the extent
practicable. Monitoring zones provide utility for observing by
establishing monitoring protocols for areas adjacent to the shutdown
zones. Monitoring zones enable observers to be aware of and communicate
the presence of marine mammals in the project areas outside the
shutdown zones and thus prepare for a potential cessation of activity
should the animal enter the shutdown zone.
Pre-Activity Monitoring
Prior to the start of daily in-water construction activity, or
whenever a break in pile driving of 30 minutes or longer occurs, PSOs
would observe the shutdown and monitoring zones for a period of 30
minutes. The shutdown zone would be considered cleared when a marine
mammal has not been observed within the zone for that 30-minute period.
If a marine mammal is observed within the shutdown zones listed in
Table 9, pile driving activity would be delayed or halted. If work
ceases for more than 30 minutes, the pre-activity monitoring of the
shutdown zones would commence. A determination that the shutdown zone
is clear must be made during a period of good visibility (i.e., the
entire shutdown zone and surrounding waters must be visible to the
naked eye).
Soft Start Procedures
Soft start procedures provide additional protection to marine
mammals by providing warning and/or giving marine mammals a chance to
leave the area prior to the hammer operating at full capacity. For
impact pile driving, contractors would be required to provide an
initial set of three strikes from the hammer at reduced energy,
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. Soft start would be implemented at the start of
each day's impact pile driving and at any time following cessation of
impact pile driving for a period of 30 minutes or longer.
Based on our evaluation of MOS's proposed measures, as well as
other measures considered by NMFS, NMFS has preliminarily determined
that the proposed mitigation measures provide the means effecting the
least practicable impact on the affected species or stocks and their
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. 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 activity; 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.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
conditions in this section and the IHA. Marine mammal monitoring during
pile driving activities would be conducted by PSOs meeting NMFS'
following requirements:
<bullet> Independent PSOs (i.e., not construction personnel) who
have no other assigned tasks during monitoring periods would be used;
[[Page 23641]]
<bullet> At least one PSO would have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
<bullet> Other PSOs may substitute education (degree in biological
science or related field) or training for experience; and
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator would be designated. The lead
observer would be required to have prior experience working as a marine
mammal observer during construction.
PSOs must have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
<bullet> MOS must employ up to five PSOs during all pile driving
activities depending on the size of the monitoring and shutdown zones.
A minimum of two PSOs (including the lead PSO) must be assigned to the
active pile driving location to monitor the shutdown zones and as much
of the Level B harassment zones as possible.
<bullet> MOS must establish the following monitoring locations with
the best views of monitoring zones as described in the IHA and
Application.
<bullet> Up to five monitors will be used at a time depending on
the size of the monitoring area. PSOs would be deployed in strategic
locations around the area of potential effects at all times during in-
water pile driving and removal. PSOs will be positioned at locations
that provide full views of the impact hammering monitoring zone and the
Level A harassment Shutdown Zones. The stations will be at the Railroad
Dock, Yakutania Point, and Dyea Point. The vibratory monitoring zone
will be monitored using PSOs stationed on boats anchored near the
shoreline. All PSOs would have access to high-quality binoculars, range
finders to monitor distances, and a compass to record bearing to
animals as well as radios or cells phones for maintaining contact with
work crews.
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
would record all incidents of marine mammal occurrence, regardless of
distance from activity, and would document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than 30 minutes.
MOS shall conduct briefings between construction supervisors and
crews, PSOs, MOS staff prior to the start of all pile driving
activities and when new personnel join the work. These briefings would
explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
Acoustic Monitoring
Acoustic monitoring will be conducted during in-water pile
installation and removal, for each of the three scenarios (impact
installation of steel piles, vibratory installation and removal of
steel piles, and vibratory removal of timber piles). Collection of the
acoustic data will be accomplished using a minimum of two hydrophones.
At least one land-based microphone would also be deployed to record
airborne sound levels. For underwater acoustic monitoring, the
hydrophones will be placed such that there is a direct line of acoustic
transmission through the water column between the impact or vibratory
hammer and the hydrophones, without any interposing structures
(including other piles) that could impede sound transfer, when
possible. All acoustical recordings will be conducted at least 1 meter
below the water surface and 1 meter above the sea floor, or as
applicable to optimize sound recordings in the nearshore environment.
Background noise recordings (in the absence of pile-related work) will
also be made during the study to provide a baseline background noise
profile.
All sensors, signal conditioning equipment, and sampling equipment
will be calibrated at the start of the monitoring period to National
Institute of Standards and Technology standards and will be rechecked
at the start of each day.
A stationary two-channel hydrophone recording system will be
deployed to record continuous sound associated with pile driving and
removal activities during the monitoring period. Key methodological
details are as follows:
<bullet> Prior to monitoring, water depth measurements will be made
to ensure that hydrophones will not drag on the bottom during tidal
changes. The hydrophones will be placed at least 1 meter below the
surface and 1 meter above the seafloor. The depth with respect to the
bottom may vary somewhat due to tidal changes and current effects.
<bullet> One hydrophone will be deployed to maintain a constant
distance of approximately 10 meters from the pile-related noise source,
and the other would be at a further distance from the pile-related
noise source.
<bullet> The hydrophones, signal conditioning, and recording
equipment will be configured to acquire maximum source levels without
clipping recorded data.
Post-analysis of underwater sound level signals would include the
following:
<bullet> Impact Pile Driving:
1. Determination of the maximum absolute value of the instantaneous
pressure within each strike.
2. RMS value for the period of which 90 percent of the energy is
represented (RMS 90, 5 percent to 95 percent) for each absolute peak
pile strike.
3. Peak SPL and pulse duration for each pile strike.
4. Mean and standard deviation/error of the RMS 90 percent for all
pile strikes of each pile.
5. Rise time.
6. Number of strikes per pile and per day.
7. Sound exposure level (SEL) of the single pile strike with the
absolute peak (PK), mean SEL.
8. Minimum, maximum, mean, and median cumulative SEL (cumulative
SEL = single strike SEL + 10*LOG (number of pile strikes)).
9. Frequency spectrum, between 20 Hz and 20 kHz, for up to eight
successive strikes with similar sound level.
<bullet> Vibratory Pile Driving and Removal:
1. RMS values (median, standard deviation/error, minimum, and
maximum) for each recorded pile. The 10-second, RMS-averaged values
will be used for determining the source value and extent of the 120 dB
underwater isopleth.
2. Frequency spectra will be provided for each functional hearing
group as
[[Page 23642]]
outlined in NOAA's 2018 guidance (NOAA, 2018).
3. All underwater source levels will be standardized to a reference
distance of 10 meters (33 feet).
<bullet> Post-analysis of airborne noise will be presented in an
unweighted format, and will include the following:
1. The unweighted RMS values (average, minimum, and maximum) for
each recorded pile. The average values will be used for determining the
extent of the airborne isopleths relative to species specific criteria.
2. Frequency spectra will be provided from 10 Hz to 20 kHz for
representative pile-related activity.
3. All airborne source levels will be standardized to a reference
distance of approximately 15 meters (50 feet).
<bullet> Acoustic monitoring will be performed using a standardized
method that will facilitate comparisons with other studies. In the
event that pile-related noise trends toward consistently surpassing
calculated levels, NMFS will be contacted immediately to revise
Shutdown Zones as needed.
Reporting
A draft marine mammal monitoring report will be submitted to NMFS
within 90 days after the completion of pile driving and removal
activities, or 60 days prior to a requested date of issuance from any
future IHAs for projects at the same location, whichever comes first.
The report will include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated PSO data
sheets. Specifically, the report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including the number and type of piles driven or
removed and by what method (i.e., impact or vibratory) and the total
equipment duration for vibratory removal for each pile or total number
of strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at the time of sighting;
<bullet> Time of sighting;
<bullet> Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentifiable), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
<bullet> Distance and bearing of each marine mammal observed
relative to the pile being driven for each sightings (if pile driving
was occurring at time of sighting);
<bullet> Estimated number of animals (min/max/best estimate);
<bullet> Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, sex class, etc.);
<bullet> Animal's closest point of approach and estimated time
spent within the harassment zone;
<bullet> Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
<bullet> Number of marine mammals detected within the harassment
zones and shutdown zones; by species;
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensured, and resulting changes in behavior of the
animal(s), if any; and
<bullet> If visibility degrades to where PSO(s) cannot view the
entire harassment zones, additional PSOs may be positioned so that the
entire width is visible, or work will be halted until the entire width
is visible to ensure that any humpback whales entering or within the
harassment zone are detected by PSOs.
If no comments are received from NMFS within 30 days, the draft
final report will constitute the final report. If comments are
received, a final report addressing NMFS comments must be submitted
within 30 days after receipt of comments.
Acoustic Monitoring Report
The Acoustic Monitoring Report must include:
<bullet> Type and size of pile being driven, substrate type, method
of driving during recordings (e.g., hammer model, energy), and total
pile driving duration;
<bullet> Whether a sound attenuation device is used and, if so, a
detailed description of the device and the duration of its use per
pile;
<bullet> A description of the sound monitoring equipment, including
a detailed description of the depths and locations of the hydrophones
relative to the pile being driven;
<bullet> For impact pile driving: Number of strikes and strike
rate, depth of substrate to penetrate; pulse duration and mean, median,
and maximum sound levels (dB re: 1 [micro]Pa); root mean square sound
pressure level (SPL<INF>RMS</INF>), cumulative sound exposure level
(SEL<INF>cum</INF>), peak sound pressure level (SPL<INF>peak</INF>),
and single strike exposure sound level (SEL s-s);
<bullet> For vibratory driving/removal (per pile): Duration of
driving per pile; mean, median, and maximum sound levels (dB re: 1
[micro]Pa): Root mean square sound pressure level (SPL<INF>RMS</INF>),
cumulative sound exposure level (SEL<INF>cum</INF>) (and timeframe over
which the sound is averaged);
<bullet> One-third octave band spectrum and power spectral density
plot for each pile monitored and average spectrum for each type of
driving (i.e. impact, vibratory of steel, vibratory of timber); and,
<bullet> Environmental data, including but not limited to, the
following: wind speed and direction, air temperature, humidity, surface
water temperature, water depth (at the pile and hydrophone locations),
characteristics of the bottom substrate into which the pile was driven,
wave height, weather conditions, and other factors that could
contribute to influencing the airborne and underwater sound levels
(e.g., aircraft, boats, etc.).
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the MOS must immediately
cease the specified activities and report the incident to the Office of
Protected Resources (OPR) (<a href="/cdn-cgi/l/email-protection#d28280fc9b8682fc9fbdbcbba6bda0bbbcb580b7a2bda0a6a192bcbdb3b3fcb5bda4"><span class="__cf_email__" data-cfemail="8adad8a4c3dedaa4c7e5e4e3fee5f8e3e4edd8effae5f8fef9cae4e5ebeba4ede5fc">[email protected]</span></a>), NMFS and
to the Alaska Regional Stranding Coordinator as soon as feasible. If
the death or injury was clearly caused by the specified activity, MOS
must immediately cease the specified activities until NMFS is able to
review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the IHA. The MOS must not resume their activities until notified by
NMFS. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
[[Page 23643]]
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, our analysis applies to all species listed in
Table 2 for which take could occur, given that NMFS expects the
anticipated effects of the proposed pile driving/removal on different
marine mammal stocks to be similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, NMFS has identified species-specific factors to
inform the analysis.
Pile driving activities associated with the project, as outlined
previously, have the potential to disturb or displace marine mammals.
Specifically, the specified activities may result in take, in the form
of Level B harassment and Level A harassment from underwater sounds
generated by pile driving. Potential takes could occur if individuals
are present in the ensonified zone when these activities are underway.
No serious injury or mortality would be expected, even in the
absence of required mitigation measures, given the nature of the
activities. Further, limited take by Level A harassment is anticipated
for humpback whales, minke whales, killer whales, harbor porpoise, and
Steller sea lion due to the application of planned mitigation measures,
such as shutdown zones that encompass the Level A harassment zones for
these species and the rarity of these species near the action area. The
potential for harassment would be minimized through the construction
method and the implementation of the planned mitigation measures (see
Proposed Mitigation section).
Take by Level A harassment is proposed for all species, as there is
potential for these species to be in the area. There is the possibility
that an animal could enter a Level A harassment zone without being
detected, and remain within that zone for a duration long enough to
incur PTS. However, Level A harassment of these species is proposed to
be conservative. Any take by Level A harassment is expected to arise
from, at most, a small degree of PTS (i.e., minor degradation of
hearing capabilities within regions of hearing that align most
completely with the energy produced by impact pile driving such as the
low-frequency region below 2 kHz), not severe hearing impairment or
impairment within the ranges of greatest hearing sensitivity. Animals
would need to be exposed to higher levels and/or longer duration than
are expected to occur here in order to incur any more than a small
degree of PTS.
Further, the amount of take proposed for authorization by Level A
harassment is low for both marine mammal stocks and species except
harbor seals as they are common in the area. If hearing impairment
occurs, it is most likely that the affected animal would lose only a
few decibels in its hearing sensitivity. Due to the small degree
anticipated, any PTS potential incurred would not be expected to affect
the reproductive success or survival of any individuals, much less
result in adverse impacts on the species or stock.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. However, since the hearing sensitivity of
individuals that incur TTS is expected to recover completely within
minutes to hours, it is unlikely that the brief hearing impairment
would affect the individual's long-term ability to forage and
communicate with conspecifics, and would therefore not likely impact
reproduction or survival of any individual marine mammal, let alone
adversely affect rates of recruitment or survival of the species or
stock.
The Level A harassment zones identified in Table 6 are based upon
an animal's exposure to pile driving of up to 5 steel piles or 18
timber piles removed per day. Given the short duration to impact drive
or vibratory install or extract each pile and break between pile
installations (to reset equipment and move piles into place), an animal
would have to remain within the area estimated to be ensonified above
the Level A harassment threshold for multiple hours. This is highly
unlikely given marine mammal movement in the area. If an animal was
exposed to accumulated sound energy, the resulting PTS would likely be
small (e.g., PTS onset) at lower frequencies where pile driving energy
is concentrated, and unlikely to result in impacts to individual
fitness, reproduction, or survival.
The nature of the pile driving project precludes the likelihood of
serious injury or mortality. For all species and stocks, take would
occur within a limited, confined area (adjacent to the project site) of
the stock's range. Level A and Level B harassment will be reduced to
the level of least practicable adverse impact through use of mitigation
measures described herein. Further, the amount of take proposed to be
authorized is small when compared to stock abundance.
Behavioral responses of marine mammals to pile driving and removal
in Taiya Inlet are expected to be mild, short term, and temporary.
Marine mammals within the Level B harassment zones may not show any
visual cues they are disturbed by activities or they could become
alert, avoid the area, leave the area, or display other mild responses
that are not observable, such as changes in vocalization patterns.
Given that pile driving and removal would occur for only a portion of
the project's duration, any harassment occurring would be temporary.
Additionally, many of the species present in region would only be
[[Page 23644]]
present temporarily based on seasonal patterns or during transit
between other habitats. These temporarily present species would be
exposed to even smaller periods of noise-generating activity, further
decreasing the impacts.
For all species, there are no known BIA near the project area that
would be impacted by MOS's planned activities. While there is a Steller
sea lion haulout at the end of Taiya inlet at Taiya point, this is
approximately 13,300-m from the project site. Additionally, there is a
rookery at Gran Point, which is Steller sea lion critical habitat,
though this is outside the project area around 24 miles (38.6 km) from
Skagway. Lastly, there is a summer feeding ground for humpback whales
in Lynn Canal, however this is outside of Taiya Inlet, and
approximately 50 miles (80.5 km) from Skagway.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on each stock's ability
to recover. In combination, we believe that these factors, as well as
the available body of evidence from other similar activities,
demonstrate that the potential effects of the specified activities will
have only minor, short-term effects on individuals. The specified
activities are not expected to impact rates of recruitment or survival
and will therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> Authorized Level A harassment would be very small amounts
and of low degree;
<bullet> For all species, Taiya Inlet is a very small and
peripheral part of their range;
<bullet> The intensity of anticipated takes by Level B harassment
is relatively low for all stocks. Level B harassment would be primarily
in the form of behavioral disturbance, resulting in avoidance of the
project areas around where impact or vibratory pile driving is
occurring, with some low-level TTS that may limit the detection of
acoustic cues for relatively brief amounts of time in relatively
confined footprints of the activities;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
<bullet> The ensonified areas are very small relative to the
overall habitat ranges of all species and stocks, and would not
adversely affect ESA-designated critical habitat for any species or any
areas of known biological importance;
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and
<bullet> MOS would implement mitigation measures including soft
starts and shutdown zones to minimize the numbers of marine mammals
exposed to injurious levels of sound, and to ensure that take by Level
A harassment is, at most, a small degree of PTS.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only small numbers of incidental take may be
authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The amount of take NMFS proposes to authorize is below one-third of
the estimated stock abundance for all species. This is likely a
conservative estimate because we assume all takes are of different
individual animals, which is likely not the case. Some individuals may
return multiple times in a day, but PSOs would count them as separate
takes if they cannot be individually identified.
The most recent estimate for the Alaska stock of Dall's porpoise
was 13,110 animals, however this number just accounts for a portion of
the stock's range. Therefore, the 183 takes of this stock proposed for
authorization is believed to be an even smaller portion of the overall
stock abundance.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
In the Skagway area, sea lions and harbor seals are available for
subsistence harvest authorized under the MMPA. The subsistence areas
used by the Hoonah and Angoon communities are in the vicinity of the
project area, but will not directly overlap with the project areas.
During subsistence harvest in Southeast Alaska in 2012, the most recent
year of available data from the Alaska Department of Fish and Game, 595
harbor seals were taken, while only 9 sea lions were taken in the
region (Wolfe et al., 2013). The proposed Project at worst may cause
short-term disturbance to sea lions and harbor seals in the area.
The proposed activity will take place in Taiya Inlet, and no
activities overlap with subsistence hunting areas; therefore, there are
no relevant subsistence uses of marine mammals adversely impacted by
this action. The proposed project is not likely to adversely impact the
availability of any marine mammal species or stocks that are commonly
used for subsistence purposes or to impact subsistence harvest of
marine mammals in the region because:
<bullet> Construction activities are localized and temporary;
[[Page 23645]]
<bullet> Mitigation measures will be implemented to minimize
disturbance of marine mammals in the action area; and,
<bullet> The project will not result in significant changes to
availability of subsistence resources.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from MOS's
proposed activities.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the Alaska Regional
Office.
NMFS is proposing to authorize take of the Central North Pacific
stock of humpback whale and the Western US stock of Steller sea lion,
which are listed or include individuals that are listed under the ESA.
The Permits and Conservation Division has requested initiation of
section 7 consultation with the Alaska Region for the issuance of this
IHA. NMFS will conclude the ESA consultation prior to reaching a
determination regarding the proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to MOS for conducting construction in Skagway, Alaska
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
terminal redevelopment project. We also request comment on the
potential renewal of this proposed IHA as described in the paragraph
below. Please include with your comments any supporting data or
literature citations to help inform decisions on the request for this
IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: April 13, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-08186 Filed 4-17-23; 8:45 am]
BILLING CODE 3510-22-P
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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.