[Federal Register Volume 82, Number 128 (Thursday, July 6, 2017)]
[Notices]
[Pages 31400-31428]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-14157]
[[Page 31399]]
Vol. 82
Thursday,
No. 128
July 6, 2017
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to the Sand Point City Dock Replacement
Project in Sand Point, Alaska; Notice
Federal Register / Vol. 82 , No. 128 / Thursday, July 6, 2017 /
Notices
[[Page 31400]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XF370
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Sand Point City Dock
Replacement Project in Sand Point, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
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SUMMARY: NMFS has received an application from the Alaska Department of
Transportation and Public Facilities (ADOT&PF) for an Incidental
Harassment Authorization (IHA) to take marine mammals, by harassment,
incidental to Sand Point City Dock Replacement Project in Sand Point,
Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue an IHA to ADOT&PF to
incidentally take marine mammals during the specified activities.
DATES: Comments and information must be received no later than August
7, 2017.
ADDRESSES: Comments on the applications should be addressed to Jolie
Harrison, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service. Physical comments should
be sent to 1315 East-West Highway, Silver Spring, MD 20910 and
electronic comments should be sent to [email protected].
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 received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted to the Internet at
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm 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: Rob Pauline, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the applications
and supporting documents, as well as a list of the references cited in
this document, may be obtained by visiting the Internet at:
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of
problems accessing these documents, please call the contact listed
above.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
The MMPA states that the term ``take'' means to harass, hunt,
capture, kill or attempt to harass, hunt, capture, or kill any marine
mammal.
Except with respect to certain activities not pertinent here, 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).
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 the proposed action with respect to environmental
consequences on the human environment. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review. This
action is consistent with categories of activities identified in CE B4
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.
Summary of Request
On September 16, 2016, NMFS received an application from ADOT&PF
for the taking of marine mammals incidental to replacing the city dock
in Sand Point, Alaska. On April 11, 2017, ADOT&PF submitted a revised
application that NMFS determined was adequate and complete. ADOT&PF
proposes to conduct in-water activities that may incidentally take, by
Level A and Level B harassment, marine mammals. Proposed activities
included as part of the Sand Point City Dock Replacement Project with
potential to affect marine mammals include impact hammer pile driving
and vibratory pile driving and removal. This IHA would be valid from
August 1, 2018 through July 31, 2019.
Species with the expected potential to be present during the
project timeframe include harbor seal (Phoca vitulina), Steller sea
lion (Eumetopias jubatus), harbor porpoise (Phocoena phocoena), Dall's
porpoise (Phocoenoides dalli), killer whale (Orcinus orca), humpback
whale (Megaptera novaeangliae), fin whale (Balaenoptera physalus), gray
whale (Eschrichtius robustus), and minke whale (Balaenoptera
acutorostrata).
Description of Specified Activities
Overview
ADOT&PF proposes to construct a new dock in Sand Point, Alaska. The
existing city dock was built in 1984 and is in need of replacement, as
it is nearing the end of its operational life due to corrosion and
wear. The dock receives barge service from Seattle weekly throughout
the year. The dock also regularly handles processed seafood. Given the
lack of road access to Sand Point, the city dock is an essential
component of infrastructure providing
[[Page 31401]]
critical access between Sand Point and the Pacific Northwest region.
Impact and vibratory driving of piles and vibratory pile removal is
expected to take place over a total of approximately 32 working days
within a 5-month window from August 1, 2018 through December 31, 2018.
However, due to the potential for unexpected delays, up to 40 working
days may be required. ADOT&PF is asking for the proposed IHA to be
valid for a period of one year. The new dock would be supported by
approximately 52 round, 30-inch-diameter, 100-foot-long permanent steel
pipe piles. Fender piles installed at the dock face would be 8 round,
24-inch-diameter, 80-foot-long permanent steel pipe piles. The single
mooring dolphin would consist of 3 round, 24-inch-diameter, 120-foot-
long permanent battered steel pipe piles. This equates to a total of 63
permanent piles. Up to 90 temporary piles would be installed and
removed during construction of the dock and would be either H-piles or
pipe piles with a diameter of less than 24 inches.
Dates and Duration
In-water pile driving and extraction activities are expected to
take place over a total of approximately 32 working days within a 5-
month window from August 1, 2018 through December 31, 2018. ADOT&PF has
requested that the proposed IHA be valid for a period of one year in
case there are delays. Table 1 illustrates the anticipated number of
days required for installation and removal of various pile types. Pile
driving and removal may occur for up to 4.5 hours per day.
Table 1--Estimated Number of Days Required for Pile Installation and
Removal
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Number of
Activity piles Days required
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Support pile installation............... 52 13
Temporary pile installation and removal. 90 15
Dolphin pile installation............... 3 2
Fender pile installation................ 8 2
-------------------------------
Total Days.......................... .............. 32
Total Days with 25 percent .............. 40
contingency........................
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Specified Geographic Region
The Sand Point city dock is located in the city of Sand Point,
Alaska, on the northwest side of Popof Island, in the western Gulf of
Alaska. Sand Point is part of the Aleutians East Borough and is located
approximately 10 miles (16 kilometers) south of the Alaska Peninsula.
Popof Island is one of the Shumagin Islands in the western Gulf of
Alaska and is approximately 16 kilometers (10 miles) long, 8 kilometers
(5 miles) wide, and covers 93.7 square kilometers (36.2 square miles).
It is located immediately east of the much larger Unga Island, and
Popof Strait separates the two islands. The City of Sand Point is the
largest community in the Shumagin Islands. See Figure 1-1 in ADOT&PF's
Application.
The Sand Point city dock is located in Humboldt Harbor, on the
southwest side of the city of Sand Point. The existing dock is located
on the causeway of Sand Point's ``New Harbor'' at the end of Boat
Harbor Road, and the proposed replacement dock is proposed to be
located immediately adjacent to (southwest of) the existing city dock
along the causeway, which also serves as the breakwater for the New
Harbor. See Figure 1-2 in ADOT&PF's Application.
Detailed Description of Specified Activity
The proposed action includes pile installation and removal of the
new city dock and the deposition of shot rock fill adjacent to the
existing causeway (See Figure 5-1 in Application). New shot rock fill
would be placed on the seaward side of the existing causeway to support
dock construction and create an additional upland area for safe
passenger staging and maneuvering of equipment. Pile installation and
removal activities will potentially result in take of marine mammals.
There is no mapped high tide line at Sand Point, and, therefore,
engineers will use Mean Higher High Water (MHHW) to determine the
placement of fill. This fill would be placed above and below MHHW to
increase the causeway's areal extent and would be stabilized through
the use of new and salvaged armor rock protection. Approximately 38,600
square feet of fill and 28,500 square feet of armor rock would be
required for breakwater expansion. Shot rock fill deposition activities
are not expected to generate underwater sound at levels that would
result in Level A or Level B harassment. Therefore, this specific
activity will not result in take of marine mammal and will not be
discussed further.
Following deposition of fill and prior to placement of armor rock,
round steel piles would be installed to support the new city dock
foundation and mooring dolphins. As noted previously, the proposed
project will require installation of 30-inch and 24-inch, permanent
steel piles. This equates to a total of 63 permanent piles as shown in
Table 2 below. It is anticipated that an ICE 44B or APE 200-6 model
vibratory driver or equivalent and a Delmag D62 diesel impact hammer or
equivalent would be used to install the piles. Project design engineers
anticipate an impact strike rate of approximately 40 strikes per
minute, based on substrate density, pile types, and hammer type, which
equates to approximately 1,000 strikes for each 30-inch dock support
pile, 400 strikes for each dolphin pile, and 120 strikes for each
fender pile.
Permanent dock support piles would be installed using both
vibratory and impact hammers; both methods of installation typically
occur within the same day. Permanent piles are first installed with a
vibratory hammer for approximately 45 minutes to insert the pile
through the overburden sediment layer and into the bearing layer. The
vibratory hammer is then replaced with the impact hammer, which is used
to install the pile for the last 15 to 20 feet (approximately 25
minutes). Up to four permanent piles would be installed per day, for a
total of 180 minutes of vibratory and 100 minutes of impact
installation per day. Installation of permanent piles would require
about 13 days of effort (52 permanent piles/4 permanent piles per day =
13 days).
Installation of the eight fender piles is anticipated to occur over
2 days (after installation of all dock support piles), at a production
rate of four fender piles per day (8 fender piles/4 fender piles per
day = 2 days). Each fender pile would require 30 minutes of vibratory
installation and 3 minutes of impact installation, for a total of 120
minutes of vibratory and 12 minutes of impact
[[Page 31402]]
installation each day. No temporary piles would be required for fender
pile installation because they would be installed along the completed
dock face.
Installation of three 24-inch permanent battered pipe piles for the
dolphin would also require the installation and removal of four
temporary piles (either <24 inch diameter or H-piles) to support the
template. Installation of the dolphin piles will occur over 2 days,
with one or two dolphin piles installed per day for a total of 3
dolphin piles. Thirty minutes of vibratory installation and 10 minutes
of impact installation are anticipated per permanent dolphin pile, for
a total of no more than 60 minutes of vibratory installation and 20
minutes of impact installation per day. Installation and removal of the
temporary piles for the dolphin are included in the calculations for
temporary piles above.
Two or more temporary piles would be used to support a template to
facilitate installation of two to four permanent dock support piles.
Template configuration, including the number of permanent piles that
could be installed at once and the number of temporary piles required
to support the template, would be determined by the contractor. Four
additional temporary piles would support the template for the dolphin.
In all, up to 90 temporary piles would be installed and removed during
construction of the dock and dolphin. Temporary piles would be either
H-piles or pipe piles with a diameter of less than 24 inches.
Temporary piles would be installed and removed during construction
of the dock by vibratory methods only. Removal and installation of the
temporary piles that support the template typically occur within the
same day, with additional time required for installation of the
template structure, which would include welding, surveying the
location, and other activities. Each temporary pile would be installed
in approximately 15 minutes and removed in approximately 15 minutes. Up
to six temporary piles would be installed and removed per day, for a
total of up to 180 minutes of vibratory installation and removal per
day. Installation of temporary piles, including those required to
support construction of the dolphin, would require about 15 total days
of effort (90 temporary piles/6 temporary piles per day = 15 days).
Total driving time for the proposed project would consist of
approximately 22 hours of impact driving and 85 hours of vibratory
driving and removal.
Following initial pile installation of permanent dock support
piles, the mud accumulation on the inside of each pile would be augured
out and the piles filled with concrete to provide additional moment
capacity and corrosion resistance. An auger with a crane-mounted rotary
head would be used for pile clearing. These activities are not
anticipated to result in underwater sound levels that would meet Level
A or Level B harassment criteria and, therefore, will not be discussed
further.
Table 2--Pile Details and Estimated Effort Required for Pile Installation
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Estimated Anticipated
Pile type Diameter Number of Maximum piles Hours per day minutes per days of effort
piles per day pile \1\
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Vibratory Installation or Removal
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Permanent support pile.................... 30''........................ 52 4 3 45 13
Permanent dolphin pile.................... 24''........................ 3 2 1 30 2
Permanent fender pile..................... 24''........................ 8 4 2 30 2
Installation, temporary support pile...... <24'' or H-pile............. 90 6 1.5 15 15
Removal, temporary support pile........... <24'' or H-pile............. 90 6 1.5 15 15
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Impact Installation
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Permanent support pile.................... 30''........................ 52 4 1.667 25 13
Permanent dolphin pile.................... 24''........................ 3 2 0.33 10 2
Permanent fender pile..................... 24''........................ 8 4 0.20 3 2
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\1\ Vibratory and impact driving of each permanent pile will occur on the same day. Installation and removal of each temporary piles will occur on the
same day.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in the document (Mitigation section and
Monitoring and Reporting section).
Description of Marine Mammals in the Area of Specified Activities
We have reviewed the applicants' species information--which
summarizes available information regarding status and trends,
distribution and habitat preferences, behavior and life history, and
auditory capabilities of the potentially affected species--for accuracy
and completeness and refer the reader to Sections 3 and 4 of the
application, as well as to NMFS's Stock Assessment Reports (SAR;
www.nmfs.noaa.gov/pr/sars/). Additional general information about these
species (e.g., physical and behavioral descriptions) may be found on
NMFS's Web site (www.nmfs.noaa.gov/pr/species/mammals/).
Table 3 lists all species with expected potential for occurrence in
Sand Point and summarizes information related to the population or
stock, including potential biological removal (PBR), where known. For
taxonomy, we follow Committee on Taxonomy (2016). PBR, 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, is considered in concert with known sources of ongoing
anthropogenic mortality to assess the population-level effects of the
anticipated mortality from a specific project (as described in NMFS's
SARs). While no mortality is anticipated or authorized here, PBR and
annual serious injury and mortality are included here as gross
indicators of the status of the species and other threats. Species that
could potentially occur in the proposed survey areas but are not
expected to have reasonable potential to be harassed by pile driving
and removal activities are described briefly but omitted from further
analysis. These include extralimital species, which are species that do
not normally occur in a given area but for which there are one
[[Page 31403]]
or more occurrence records that are considered beyond the normal range
of the species. For status of species, we provide information regarding
U.S. regulatory status under the MMPA and ESA.
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 area. NMFS's stock
abundance estimates for most species represent the total estimate of
individuals within the geographic area, if known, that comprises that
stock.
The marine waters of the Shumagin Islands support many species of
marine mammals, including pinnipeds and cetaceans; however, the number
of species regularly occurring near the project area is limited (Table
3). Steller sea lions are the most common marine mammals in the project
area, and are part of the western Distinct Population Segment (wDPS),
which is listed as endangered under the ESA. Humpback whales, including
the ESA-listed Western North Pacific DPS (endangered) and Mexico DPS
(threatened), as well as ESA-listed fin whales (endangered), may occur
in the project area, but far less frequently and in lower abundance
than Steller sea lions. Harbor seals and harbor porpoises may be
observed in the project area. Gray whales, minke whales, killer whales,
and Dall's porpoises also have the potential to occur in or near the
project area, although in limited numbers.
North Pacific right whales (Eubalaena japonica) are very rare in
general and extremely unlikely to occur within the project area. Other
animals whose range overlaps with the project area include the northern
fur seal (Callorhinus ursinus), ribbon seal (Histriophoca fasciata),
spotted seal (Phoca largha), and Pacific white-sided dolphin
(Lagenorhynchus obliquidens). However, occurrences of these species
have not been reported locally and take is not anticipated or proposed.
The ranges of sperm whales (Physeter macrocephalus) and Cuvier's beaked
whales (Ziphius cavirostris) include the Shumagin Islands. However,
these species generally inhabit deep waters and would be unlikely to
occur in the relatively shallow waters of Popof Strait. Therefore, take
is not proposed for either of these species. The species listed in this
paragraph will not be discussed further.
All values presented in Table 3 are the most recent available at
the time of publication and are available in the 2015 SARs (Muto et
al., 2016) and draft 2016 SARs (Muto et al., 2016b) available online
at: www.nmfs.noaa.gov/pr/sars/draft.htm).
Table 3--Marine Mammal Species Potentially Present in the Project Area
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Stock abundance
ESA/MMPA status; (CV, Nmin, most Relative
Species Stock strategic (Y/N) recent abundance PBR \3\ Annual M/SI \4\ occurrence near
\1\ survey) \2\ Sand Point
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Phocoenidae (porpoises)
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Dall's porpoise................. Alaska............. -; N 83,400 (0.097; n/ Undet............. 38................ Rare.
a; 1993).
Harbor porpoise................. Gulf of Alaska..... -; Y 25,987 (0.214; n/ Undet............. 72................ Common.
a; 1998).
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae (dolphins)
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Killer whale.................... Eastern North -; N 2,347 (n/a; 2,347; 24................ 1................. Uncommon.
Pacific Alaska 2012).
Resident.
Eastern North -; N 587 (n/a; 587; 5.9............... 1................. Uncommon.
Pacific Gulf of 2012).
AK, Aleutian
Islands, and
Bering Sea
Transient.
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Balaenopteridae
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Humpback whale.................. Central North n/a Y 10,103 (0.300; 83................ 24................ Uncommon.
Pacific. 7,890; 2006).
Western North n/a\5\; Y 1,107 (0.300; 865; 3................. 2.6............... Uncommon.
Pacific. 2006).
Fin whale....................... Northeast Pacific.. E/D; Y 1,368 (n/a, 1,036; 2.1............... 0.6............... Rare.
2010).
Minke whale..................... Alaska............. -; N .................. .................. 0................. Rare.
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Eschrichtiidae
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Gray whale...................... Eastern North -; N 20,990 (0.05; 624............... 132............... Rare.
Pacific. 20,125; 2011).
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and sea lions)
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Steller sea lion................ wDPS............... E/D; S 50,983 (n/a; 306............... 236............... Very common.
50,983; 2015).
[[Page 31404]]
Family Phocidae (earless seals)
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Harbor seal..................... (Cook Inlet/ -; N 27,386 (n/a; 770............... 234............... Occasional.
Shelikof Strait. 25,651, 2011).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks of
pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction factor derived from knowledge
of the specie's (or similar species') life history to arrive at a best abundance estimate; therefore, there is no associated CV. In these cases, the
minimum abundance may represent actual counts of all animals ashore.
\3\ Potential biological removal, 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 size (OSP).
\4\ 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.
\5\ The newly defined DPSs do not currently align with the stocks defined under the MMPA.
Cetaceans
Dall's Porpoise
Dall's porpoises are found throughout the North Pacific, from
southern Japan to southern California north to the Bering Sea. All
Dall's porpoises found in Alaska are members of the Alaska stock. This
species can be found in offshore, inshore, and nearshore habitat, but
prefer waters more than 180 meters (600 feet) deep (Jefferson 2009).
Dall's porpoises, like all marine mammals, are protected under the
MMPA, but they are not listed under the ESA. Insufficient data are
available to estimate current population trends, but the species is
considered reasonably abundant. The current population estimate for the
species is 1.2 million, and the Alaska stock was last estimated at
83,400 individuals in 1993 (Muto et al., 2016a).
There currently is no information on the presence or abundance of
Dall's porpoises in the Shumagin Islands. No sightings of Dall's
porpoises have been documented in Humboldt Harbor and they are not
expected to occur there, although they may occur in deeper waters
farther offshore (HDR 2017).
Dall's porpoises generally occur in groups of 2 to 20 individuals,
but have also been recorded in groups numbering in the hundreds. In
Alaska, the average group size ranges from 2.7 to 3.7 individuals (Wade
et al., 2003). They are commonly observed bowriding vessels or large
cetaceans. Common prey includes a variety of small schooling fishes
(such as herrings, anchovies, mackerels, and sauries) and cephalopods.
Dall's porpoises may migrate between inshore and offshore areas, make
latitudinal movements, or make short seasonal migrations, but these
movements are generally not consistent (Jefferson 2009).
Harbor Porpoise
In the eastern North Pacific Ocean, the harbor porpoise ranges from
Point Barrow, along the Alaska coast, and down the west coast of North
America to Point Conception, California. Harbor porpoises frequent
primarily coastal waters in the Gulf of Alaska and Southeast Alaska
(Dahlheim et al., 2000), and occur most frequently in waters less than
100 meters (328 feet) deep (Hobbs and Waite 2010). The Gulf of Alaska
stock ranges from Cape Suckling to Unimak Pass (Muto et al., 2016a).
In Alaska, harbor porpoises are currently divided into three
stocks, based primarily on geography: the Bering Sea stock, the
Southeast Alaska stock, and the Gulf of Alaska stock. In areas outside
Alaska, studies have shown that stock structure is more finely scaled
than is reflected in the Alaska Stock Assessment Reports. However, no
data are yet available to define stock structure for harbor porpoises
on a finer scale in Alaska (Allen and Angliss 2014). Only the Gulf of
Alaska stock is considered in this application because the other stocks
occur outside the geographic area under consideration.
Harbor porpoises are neither designated as depleted under the MMPA
nor listed as threatened or endangered under the ESA. Because the most
recent abundance estimate is more than eight years old and information
on incidental harbor porpoise mortality in commercial fisheries is not
well understood, the Gulf of Alaska stock of harbor porpoises is
classified as strategic. Population trends and status of this stock
relative to optimum sustainable population size are currently unknown.
The number of harbor porpoises in the Gulf of Alaska stock was
assessed in 1998 at 31,046. The current minimum population estimate for
harbor porpoises in the Gulf of Alaska, calculated using the potential
biological removal guidelines, is 25,987 individuals (Muto et al.,
2016b). No reliable information is available to determine trends in
abundance.
Survey data for the Shumagin Islands are not available. Anecdotal
observations indicate that harbor porpoises are uncommon in Humboldt
Harbor proper but may occur in nearby waters (HDR 2017).
Harbor porpoises forage in waters less than 200 meters (656 feet)
to bottom depth on small pelagic schooling fish such as herring, cod,
pollock, octopus, smelt, and bottom-dwelling fish, occasionally feeding
on squid and crustaceans (Bj[oslash]rge and Tolley 2009; Wynne et al.,
2011).
Killer Whale
Killer whales have been observed in all the world's oceans, but the
highest densities occur in colder and more productive waters found at
high latitudes (NMFS 2016a). Killer whales occur along the entire
Alaska coast, in British Columbia and Washington inland waterways, and
along the outer coasts of Washington, Oregon, and California (NMFS
2016a). Based on data regarding association patterns, acoustics,
movements, and genetic differences, eight killer whale stocks are now
recognized within the Pacific U.S. Exclusive Economic Zone, seven of
which occur in Alaska: (1) The Alaska resident stock; (2) the Northern
resident
[[Page 31405]]
stock; (3) the Southern resident stock; (4) the Gulf of Alaska,
Aleutian Islands, and Bering Sea transient stock; (5) the AT1 transient
stock; (6) the West Coast transient stock, occurring from California
through southeastern Alaska; and (7) the Offshore stock (Muto et al.,
2016a). Only the Alaska resident stock and the Gulf of Alaska, Aleutian
Islands, and Bering Sea transient stock are considered in this
application because other stocks occur outside the geographic area
under consideration. Neither of these stocks of killer whales is
designated as depleted or strategic under the MMPA or listed as
threatened or endangered under the ESA.
The Alaska resident stock occurs from southeastern Alaska to the
Aleutian Islands and Bering Sea. The transient stock occurs primarily
from Prince William Sound through the Aleutian Islands and Bering Sea.
The abundance of the Alaska resident stock of killer whales is
currently estimated at 2,347 individuals, and the Gulf of Alaska,
Aleutian Islands, and Bering Sea transient stock is estimated at 587
individuals. The Gulf of Alaska component of the transient stock is
estimated to include 136 of the 587 individuals (Muto et al., 2016a).
The abundance of the Alaska resident stock is likely underestimated
because researchers continue to encounter new whales in the Gulf of
Alaska and western Alaska waters. At present, reliable data on trends
in population abundance for both stocks are unavailable.
Line transect surveys conducted in the Shumagin Islands between
2001 and 2003 did not record any resident killer whales, but did record
a relatively high abundance of transient killer whales (Zerbini et al.,
2007). The population trend of the transient stock of killer whales in
Alaska has remained stable since the 1980s (Muto et al., 2016b).
Anecdotal observations indicate that killer whales are not often seen
in the vicinity of Sand Point, including Popof Strait (HDR 2017).
Distinct ecotypes of killer whales include transients that hunt and
feed primarily on marine mammals and residents that forage primarily on
fish. Transient killer whales feed primarily on harbor seals, Dall's
porpoises, harbor porpoises, and sea lions. Resident killer whale
populations in the eastern North Pacific feed mainly on salmonids,
showing a strong preference for Chinook salmon (Muto et al., 2016b).
Transient whales are often found in long-term stable social units
(pods) of fewer than 10 whales, which are generally smaller than
resident social groups. Resident-type killer whales occur in larger
pods of whales that are seen in association with one another more than
50 percent of the time (Muto et al., 2016b).
Humpback Whale
There are five stocks of humpback whales defined under the MMPA,
two of which occur in Alaska: The Central North Pacific Stock, which
consists of winter/spring populations in the Hawaiian Islands which
migrate primarily to northern British Columbia/Southeast Alaska, the
Gulf of Alaska, and the Bering Sea/Aleutian Islands; and the Western
North Pacific stock, which consists of winter/spring populations off
Asia which migrate primarily to Russia and the Bering Sea/Aleutian
Islands (Muto et al., 2016b). The Western North Pacific stock is found
in coastal and inland waters around the Pacific Rim from Point
Conception, California, north to the Gulf of Alaska and the Bering Sea,
and west along the Aleutian Islands to the Kamchatka Peninsula and into
the Sea of Okhotsk and north of the Bering Strait, which are historical
feeding grounds (Muto et al., 2016b). Information from a variety of
sources indicates that humpback whales from the Western and Central
North Pacific stocks mix to a limited extent on summer feeding grounds
ranging from British Columbia through the central Gulf of Alaska and up
to the Bering Sea (Muto et al., 2016).
Humpback whales worldwide were designated as ``endangered'' under
the Endangered Species Conservation Act in 1970, and were listed under
the ESA from its inception in 1973 until 2016. On September 8, 2016,
NMFS published a final decision which changed the status of humpback
whales under the ESA (81 FR 62259), effective October 11, 2016. The
decision recognized the existence of 14 DPSs based on distinct breeding
areas in tropical and temperate waters. Five of the 14 DPSs were
classified under the ESA (4 endangered and 1 threatened), while the
other 9 DPSs were delisted. Humpback whales found in the Shumagin
Islands are predominantly members of the Hawaii DPS, which are not
listed under the ESA. However, based on a comprehensive photo-
identification study, members of both the Western North Pacific DPS
(ESA-listed as endangered) and Mexico DPS (ESA-listed as threatened)
are known to occur in the Gulf of Alaska and Aleutian Islands. Members
of different DPSs are known to intermix on feeding grounds; therefore,
all waters off the coast of Alaska should be considered to have ESA-
listed humpback whales. According to Wade et al. (2016), there is a 0.5
percent (CV [coefficient of variation]=0.001) probability that a
humpback whale observed in the Gulf of Alaska is from the Western North
Pacific DPS. The probability of a humpback whale being from the Mexico
DPS is 10.5 percent (CV=0.16). The remaining 89 percent (CV=0.01) of
individuals in the Gulf of Alaska are likely members of the Hawaii DPS
(Wade et al., 2016).
The current abundance estimate for humpback whales in the Pacific
Ocean is approximately 16,132 individuals. The Hawaii DPS is the
largest stock, with approximately 11,398 individuals (95 percent
confidence interval [CI]: 10,503-12,370), followed by the Mexico DPS
(3,264 individuals [95 percent CI: 2,912-3,659]) and the Western North
Pacific DPS (1,059 individuals [95 percent CI: 898-1,249]). Summer
abundance of humpback whales in the Gulf of Alaska, from all DPSs, is
estimated at 2,089 individuals (95 percent CI: 1,755-2,487; Wade et
al., 2016). Critical habitat has not been designated for any humpback
whale DPS.
Surveys from 2001 to 2004 estimated humpback whale abundance in the
Shumagin Islands at between 410 and 593 individuals during the summer
feeding season (July-August; Witteveen et al., 2004; Zerbini et al.,
2006). Annual vessel-based, photo-identification surveys in the
Shumagin Islands from 1999 to 2015 identified 654 unique individual
humpback whales between June and September (Witteveen and Wynne 2016).
Humpback whale abundance in the Shumagin Islands increased 6 percent
per year between 1987 and 2003 (Zerbini et al., 2006). Humpback whales
are occasionally observed in Popof Strait between Popof Island and Unga
Island (HDR 2017) and are known to feed in the waters west of the
airport (HDR 2017). They are unlikely to occur in the shallow waters of
Humboldt Harbor proper (HDR 2017) but may occur in Popof Strait in
waters ensonified by pile driving and removal activities. Humpbacks are
found in the Shumagin Islands from April or May through October or
November, and peak feeding activity occurs between June and early
September.
Large aggregations of humpback whales spend the summer and fall in
the nearshore areas of the Alaska Peninsula, Gulf of Alaska, and
Aleutian Islands. The waters of the western Gulf of Alaska support
feeding populations of humpback whales (HDR 2017). The Shumagin Islands
are considered a biologically important area for feeding
[[Page 31406]]
humpback whales in July and August (Ferguson et al., 2015).
Fin Whale
Four stocks of fin whales occur in U.S. waters: (1) Alaska
(Northeast Pacific), (2) California/Washington/Oregon, (3) Hawaii, and
(4) western North Atlantic (Aguilar 2009; Muto et al., 2016). Fin
whales in the Shumagin Islands are from the Alaska (Northeast Pacific)
stock (Muto et al., 2016z).
Fin whales were designated as ``endangered'' under the Endangered
Species Conservation Act in 1970, and have been listed under the ESA
since its inception in 1973. There are no reliable estimates of current
or historic abundance for the entire North Pacific population of fin
whales. Surveys in the Bering Sea, Aleutian Islands, and Gulf of Alaska
estimated 5,700 whales. The population in this region is thought to be
increasing at approximately 3.6 percent per year, but there is a high
degree of variability in this estimate (Zerbini et al., 2006). Critical
habitat has not been designated for the fin whale.
Vessel-based line-transect surveys of coastal waters between
Resurrection Bay and the central Aleutian Islands were completed in
July and August from 2001 to 2003. Large concentrations of fin whales
were found in the Semidi Islands, located midway between the Shumagin
Islands and Kodiak Island just south of the Alaska Peninsula. The
abundance of fin whales in the Shumagin Islands ranged from a low
estimate of 604 in 2003 to a high estimate of 1,113 in 2002. Fin whales
are uncommon in Humboldt Harbor or Popof Strait (HDR 2017).
Fin whales are found in deep offshore waters as well as in shallow
nearshore areas. Their migratory movements are complex and their
abundance can fluctuate seasonally. Fin whales often congregate in
groups of two to seven whales or in larger groups of other whale
species, including humpback and minke whales (Muto et al., 2016a). Fin
whales feed on a wide variety of organisms and their diet may vary with
season and locality.
Gray Whale
Gray whales were listed under the Endangered Species Conservation
Act in 1970 and under the ESA since its inception in 1973. However, in
1994, the eastern North Pacific (ENP) stock of gray whales was delisted
from the ESA, while the western North Pacific (WNP) stock remains
endangered. A limited number of WNP gray whales have recently been
observed off the west coast of North America in winter. However, most
gray whales found in Alaska are part of the ENP stock. The most recent
stock assessment in 2014 estimated 20,990 individuals in the ENP stock.
The WNP stock population estimate is 135 individuals (Carretta et al.,
2016). ENP gray whales spend summers feeding in the Chukchi and Bering
seas, and their breeding and calving grounds are located off Baja
California, Mexico (Caretta et al., 2016). Due to the very large range
and small population size of the WNP stock, occurrences of these
animals in the project area are highly unlikely. Therefore, take is not
anticipated or proposed and WNP whales will not be discussed further.
Gray whales pass through the Shumagin Islands from March through
May on their northward migration to the Bering and Chukchi seas. Most
individuals pass through Unimak Pass, which is located just west of the
Shumagin Islands. The Shumagin Islands are considered a biologically
important area for the gray whale due to this consistent migration
route. Gray whales pass through again from November through January on
their southern migration (NOAA 2016; Caretta et al., 2016).
Gray whales are rarely observed near Sand Point or in Humboldt
Harbor. Approximately 10 years ago, a single juvenile gray whale was
observed in Humboldt Harbor, but this individual was thought to be
separated from its family group (HDR 2017). During migration, however,
they are known to pass through Unga Strait, to the north of the project
area, or the Gorman and West Nagai straits south of the project area
(NOAA 2016).
Gray whales of the eastern North Pacific stock breed and calve in
protected bays and estuaries of Baja California, Mexico. Large
congregations form there in January and February. Between February and
May gray whales undertake long migrations to the Bering and Chukchi
seas where they disperse across the feeding grounds. Gray whales feed
on a wide variety of benthic organisms as well as planktonic and
nektonic organisms. In recent years, shifts in sub-arctic climatic
conditions have reduced the productivity of benthic communities and
have resulted in a shift in the food supply. In response, gray whales
have shifted their feeding strategies and focus almost exclusively on
the Chukchi Sea. Secondary feeding areas include the Bering Sea,
Beaufort Sea, and some individuals have been reported along the west
coast of North America as far south as California. The southerly
migration occurs from October through January (Jones and Swartz 2009;
Muto et al., 2016).
Minke Whale
Minke whales are protected under the MMPA, but they are not listed
under the ESA. The population status of minke whales is considered
stable throughout most of their range. The International Whaling
Commission has identified three stocks in the North Pacific: One near
the Sea of Japan, a second in the rest of the western Pacific (west of
180[deg] W.), and a third, less concentrated stock found throughout the
eastern Pacific. NOAA further splits this third stock between Alaskan
whales and resident whales of California, Oregon, and Washington (Muto
et al., 2016). There are no population estimates for minke whales in
Alaska; however, nearshore aerial surveys of the western Gulf of Alaska
took place between 2001 and 2003. These surveys estimated the minke
whale population in that area at approximately 1,233 individuals
(Zerbini et al., 2006).
Minke whales are common in the Aleutian Islands and north through
the Bering Sea and Chukchi Sea, but are relatively uncommon in the
Shumagin Islands and Gulf of Alaska (Muto et al., 2016, Zerbini et al.,
2006). Sightings did occur northwest of Unga Island during surveys in
2001, and northeast of Popof Island during 2002 and 2003 (Zerbini et
al., 2006).
In Alaska, the minke whale diet primarily consists of euphausiids
and walleye pollock. Minke whales are generally found in shallow,
coastal waters within 200 meters of shore (Zerbini et al., 2006) and
are almost always solitary or in small groups of 2 to 3. In Alaska,
seasonal movements are associated with feeding areas that are generally
located at the edge of the pack ice.
Pinnipeds
Steller Sea Lions
Steller sea lions are found throughout the northern Pacific Ocean,
including coastal and inland waters from Russia (Kuril Islands and the
Sea of Okhotsk), east to Alaska, and south to central California
(A[ntilde]o Nuevo Island). 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 (Allen and Angliss 2010). The eastern DPS remained
classified as threatened (62 FR 24345) until it was delisted in
November 2013. The wDPS (those individuals west of 144[deg] W.
longitude or Cape Suckling, Alaska) was upgraded to
[[Page 31407]]
endangered status following separation of the DPSs, and it remains
endangered today. Only the wDPS is considered in this application
because the range of the eastern DPS is not known to include the
project area.
From 2000-2004, non-pup Steller sea lion counts at trend sites in
the wDPS increased 11 percent. These counts suggested the first region-
wide increases for the wDPS since standardized surveys began in the
1970s, and were attributed to increased survey efforts in all regions
except the western Aleutian Islands. Annual surveys of haulouts and
rookeries in the western Gulf of Alaska since 1985 indicate a 16
percent increase in non-pup counts and 38 percent reduction in pup
counts over the 30-year period. However, since 2003, these counts have
increased by 58 percent for non-pups and 53 percent for pups (Fritz et
al., 2016a, 2016b). Annual increases for the western Gulf of Alaska
range between 3.4 and 3.8 percent for non-pup and pup counts since the
early 2000s (Muto et al., 2016a; Fritz et al., 2016a, 2016b).
The wDPS breeds on rookeries in Alaska from Prince William Sound
west through the Aleutian Islands. Steller sea lions use 38 rookeries
and hundreds of haulouts within their range in western Alaska (Allen
and Angliss 2013). Steller sea lions are not known to migrate, but
individuals may disperse widely outside the breeding season (late May
to early July). At sea, Steller sea lions are commonly found from
nearshore habitats to the continental shelf and slope.
On August 27, 1993, NMFS published a final rule designating
critical habitat for the Steller sea lion. In Alaska, designated
critical habitat includes all major Steller sea lion rookeries and
major haulouts identified in the listing notice (58 FR 45269) and
associated terrestrial, air, and aquatic zones. Critical habitat
includes a terrestrial zone that extends 0.9 kilometer (3,000 feet)
landward from each major rookery and major haulout, and an air zone
that extends 0.9 kilometer (3,000 feet) above the terrestrial zone of
each major rookery and major haulout. For each major rookery and major
haulout located west of 144[deg] W. longitude (i.e., the project area),
critical habitat includes an aquatic zone (or buffer) that extends 37
kilometers (20 nautical miles) seaward in all directions. Critical
habitat also includes three large offshore foraging areas: The Shelikof
Strait area, the Bogoslof area, and the Seguam Pass area (58 FR 45269).
The project is located within the aquatic zones (i.e., designated
critical habitat) of two designated major haulouts: Sea Lion Rocks
(Shumagins) and The Whaleback. The ensonified Level B harassment zone
related to implementation of the proposed project, described later in
the ``Estimated Take'' section, overlaps with the designated aquatic
zone or buffer of a third designated major haulout on Jude Island. No
terrestrial or in-air critical habitat of any major haulout overlaps
with the project area. The major haulout at Sea Lion Rocks (Shumagins)
is located approximately 28 kilometers (15.1 nautical miles) south of
the project site. The major haulout at The Whaleback is located
approximately 27.4 kilometers (14.8 nautical miles) east of Sand Point.
The major haulout at Jude Island is located 39.6 kilometers (21.4
nautical miles) west of Sand Point.
The project area does not overlap with the aquatic zone of any
major rookery, nor does it overlap with the three designated offshore
foraging areas. The closest designated major rookery is on the east
side of Atkins Island, which is approximately 83.3 kilometers (45
nautical miles) southeast of Sand Point. Another major rookery is
located about 85.2 kilometers (46 nautical miles) south of Sand Point
on the southwest point of Chernabura Island (Fritz et al., 2016c).
Steller sea lions are the most obvious and abundant marine mammal
in the project area, and their abundance is highly correlated with
seasonal fishing activity. Sea lions tend to congregate at the seafood
processing facility (Figure 1-3 and Figure 1-4 in the application)
during the walleye pollock (Gadus chalcogramma) fishing seasons (HDR
2017). There are four official pollock fishing seasons: The ``A''
season starts on January 20, the ``B'' season starts on March 10, the
``C'' season starts on August 25, and the ``D'' season starts on
October 1 (HDR 2017). The end dates of these seasons are variable.
Outside of the pollock seasons, there are few sea lions in the harbor.
It is suspected that sea lions are feeding on salmon during the summer
salmon runs, and are not present in high numbers around Sand Point (HDR
2017).
The closest Steller sea lion haulout to the project area is located
on Egg Island, which is approximately 6 kilometers (3.7 nautical miles)
from the project. Recent counts have not recorded any Steller sea lions
at this haulout (Fritz et al., 2016a, 2016b; HDR 2017), however, local
anecdotal reports suggest that the haulout does experience some use
(HDR). Researchers have noted as many as 10 sea lions at this haulout
in May, although these observations are not part of systematic counts
(HDR 2017). The closest rookery is located on Jude Island,
approximately 38.9 kilometers (21 nautical miles) west of Sand Point,
and had average annual counts of 214 sea lion pups from 2009-2014
(Fritz et al., 2016a). Note that these locations are not considered
major haulouts.
Sea lions have become accustomed to depredating fishing gear and
raiding fishing vessels during fishing and offloading near the project
area and they follow potential sources of food in and around the
Humboldt Harbor, waiting for opportunities to feed. The number of sea
lions in the waters near Sand Point varies depending on the season and
presence of commercial fishing vessels unloading their catch at the
seafood processing facility. The Sand Point harbormaster and seafood
processing plant foreman are the best available sources for information
on sea lion abundance at Sand Point. Information from these individuals
suggests that the highest numbers of sea lions are present during the
pollock fishing seasons. Average counts at the seafood processing
facility range from 4 to 12, but can occasionally reach as many as 20
sea lions. There are no notable differences in abundance between the
four pollock seasons. Outside of the pollock seasons, sea lions may be
present, but in small numbers (i.e., 1 or 2 individuals). Sea lions
also regularly visit other parts of Humboldt Harbor in search of
opportunistic food sources, including the small boat harbor, the New
Harbor, and City Dock (HDR 2017).
Harbor Seals
Harbor seals range from Baja California north along the west coasts
of Washington, Oregon, California, British Columbia, and Southeast
Alaska; west through the Gulf of Alaska, Prince William Sound, and the
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the
Pribilof Islands. In 2010, harbor seals in Alaska were partitioned into
12 separate stocks based largely on genetic structure (Allen and
Angliss 2010). Harbor seals in the Shumagin Islands are members of the
Cook Inlet/Shelikof Strait stock. Distribution of the Cook Inlet/
Shelikof Strait stock extends from the southwest shore of Unimak Island
east along the southern coast of the Alaska Peninsula to Elizabeth
Island off the southwest shore of the Kenai Peninsula, including Cook
Inlet, Knik Arm, and Turnagain Arm (Muto et al., 2016a).
Harbor seals are not designated as depleted under the MMPA and are
not listed as threatened or endangered under the ESA. The current
statewide abundance estimate for Alaskan harbor seals is 205,090 based
on aerial survey data collected during 1998-2011. The
[[Page 31408]]
2007 through 2011 abundance estimate for the Cook Inlet/Shelikof stock
is 27,386 (Muto et al., 2016a).
Survey data by London et al. (2015) for the Shumagin Islands in
2011 indicate that harbor seals used two haulouts in the project area
during that year. One is located on the south shore of Popof Island
south of the airport at a distance of approximately 10 km (5.5 nautical
miles) from Humboldt Harbor. The other is on the northeast shore of
Unga Island approximately 23 km (12 nautical miles) distant from the
project site. No known haulouts overlap within the Level B underwater
harassment zones estimated for the project. Aerial haulout surveys
conducted by London et al. (2015) indicated that 15 harbor seals occupy
the survey unit along the south coast of Popof Island, including the
area around Sand Point. Abundance estimates at other survey units in
the area ranged from zero on the north shore of Popof Island to 100
along the northeast coast of Unga Island. This information comes from a
single year of surveys, and standard errors on these estimates are very
high; therefore, confidence in these estimates is low (London et al.,
2015). Anecdotal observations indicate that harbor seals are uncommon
in Humboldt Harbor proper, but are occasionally observed near the
airport (HDR 2017).
Harbor seals are opportunistic feeders that forage in marine,
estuarine, and, occasionally, freshwater habitat, adjusting their
foraging behavior to take advantage of prey that is locally and
seasonally abundant (Payne and Selzer 1989). Depending on prey
availability, research has demonstrated that harbor seals conduct both
shallow and deep dives during hunting (Tollit et al., 1997). Harbor
seals haul out on rocks, reefs, beaches, and drifting glacial ice (Muto
et al., 2016a). They are non-migratory; their local movements are
associated with tides, weather, season, food availability, and
reproduction, as well as sex and age class (Muto et al., 2016a; Allen
and Angliss 2014; Boveng et al., 2012; Lowry et al., 2001; Swain et
al., 1996).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity (e.g. sound produced by pile
driving and removal) may impact marine mammals and their habitat. The
``Estimated Take'' section later in this document will include a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The ``Negligible Impact Analysis and
Determination'' section will consider the content of this section, the
``Estimated Take by Incidental Harassment'' section, and the ``Proposed
Mitigation'' section, to draw conclusions regarding the likely impacts
of pile driving and removal activities on the reproductive success or
survivorship of individuals and how those impacts on individuals are
likely affect marine mammal species or stocks.
Description of Sound Sources
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks of a sound wave; lower frequency sounds have
longer wavelengths than higher frequency sounds and attenuate
(decrease) more rapidly in shallower water. Amplitude is the height of
the sound pressure wave or the `loudness' of a sound and is typically
measured using the decibel (dB) scale. A dB is the ratio between a
measured pressure (with sound) and a reference pressure (sound at a
constant pressure, established by scientific standards). It is a
logarithmic unit that accounts for large variations in amplitude;
therefore, relatively small changes in dB ratings correspond to large
changes in sound pressure. When referring to sound pressure levels
(SPLs; the sound force per unit area), sound is referenced in the
context of underwater sound pressure to 1 microPascal ([mu]Pa). One
pascal is the pressure resulting from a force of one newton exerted
over an area of one square meter. The source level (SL) represents the
sound level at a distance of 1 m from the source (referenced to 1
[mu]Pa). The received level is the sound level at the listener's
position. Note that all underwater sound levels in this document are
referenced to a pressure of 1 [mu]Pa and all airborne sound levels in
this document are referenced to a pressure of 20 [mu]Pa.
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Rms is calculated by squaring all of the
sound amplitudes, averaging the squares, and then taking the square
root of the average (Urick, 1983). Rms accounts for both positive and
negative values; squaring the pressures makes all values positive so
that they may be accounted for in the summation of pressure levels
(Hastings and Popper, 2005). This measurement is often used in the
context of discussing behavioral effects, in part because behavioral
effects, which often result from auditory cues, may be better expressed
through averaged units than by peak pressures.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in all
directions away from the source (similar to ripples on the surface of a
pond), except in cases where the source is directional. The
compressions and decompressions associated with sound waves are
detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al.,1995), and the sound level of
a region is defined by the total acoustical energy being generated by
known and unknown sources. These sources may include physical (e.g.,
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
sound (e.g., vessels, dredging, aircraft, construction). A number of
sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient noise for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf noise becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total noise at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient noise levels, as can some fish and shrimp. The frequency band
for biological contributions is from approximately 12 Hz to over 100
kHz.
Anthropogenic: Sources of ambient noise related to human
activity include transportation (surface vessels and aircraft),
dredging and construction, oil and gas drilling and production, seismic
surveys, sonar, explosions, and ocean
[[Page 31409]]
acoustic studies. Shipping noise typically dominates the total ambient
noise for frequencies between 20 and 300 Hz. In general, the
frequencies of anthropogenic sounds are below 1 kHz and, if higher
frequency sound levels are created, they attenuate rapidly (Richardson
et al., 1995). Sound from identifiable anthropogenic sources other than
the activity of interest (e.g., a passing vessel) is sometimes termed
background sound, as opposed to ambient sound.
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 impact pile driving, vibratory pile driving and vibratory pile
extraction. The sounds produced by these activities fall into one of
two general sound types: Pulsed and non-pulsed (defined in the
following paragraphs). 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). Please see Southall et al., (2007) for an in-
depth discussion of these concepts.
Pulsed sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and
occur either as isolated events or repeated in some succession. Pulsed
sounds are all characterized by a relatively rapid rise from ambient
pressure to a maximal pressure value followed by a rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
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 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).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals,
and exposure to sound can have deleterious effects. To appropriately
assess these potential effects, it is necessary to understand the
frequency ranges marine mammals are able to hear. Current data indicate
that not all marine mammal species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008). To reflect this, Southall et al. (2007) recommended
that marine mammals be divided into functional hearing groups based on
measured or estimated hearing ranges on the basis of available
behavioral data, audiograms derived using auditory evoked potential
techniques, anatomical modeling, and other data. Note that no direct
measurements of hearing ability have been successfully completed for
mysticetes (i.e., low-frequency cetaceans). Subsequently, NMFS (2016)
described generalized hearing ranges for these marine mammal hearing
groups. Generalized hearing ranges were chosen based on the
approximately 65 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. The functional groups and
the associated frequencies are indicated below (note that these
frequency ranges correspond to the range for the composite group, with
the entire range not necessarily reflecting the capabilities of every
species within that group) (NMFS 2016):
Low-frequency cetaceans (mysticetes): Generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz, with best
hearing estimated to be from 100 Hz to 8 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz, with best hearing from 10 to
less than 100 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): Generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz.
Pinnipeds in water; Phocidae (true seals): Generalized
hearing is estimated to occur between approximately 50 Hz to 86 kHz,
with best hearing between 1-50 kHz;
Pinnipeds in water; Otariidae (eared seals): Generalized
hearing is estimated to occur between 60 Hz and 39 kHz, with best
hearing between 2-48 kHz.
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
(Kastelein et al., 2009; Reichmuth et al., 2013).
As mentioned previously in this document, nine marine mammal
species (seven cetaceans and two pinnipeds) may occur in the project
area. Of the cetaceans, four are classified as a low-frequency cetacean
(i.e., humpback whale, gray whale, fin whale, minke
[[Page 31410]]
whale), one is classified as a mid-frequency cetacean (i.e., killer
whale), and two are classified as high-frequency cetaceans (i.e.,
harbor porpoise and Dall's porpoise) (Southall et al., 2007).
Additionally, harbor seals are classified as members of the phocid
pinnipeds in water functional hearing group while Steller sea lions are
grouped under the Otariid pinnipeds in water functional hearing group.
A species' functional hearing group is a consideration when we analyze
the effects of exposure to sound on marine mammals. Marine mammal
hearing groups were also used in the establishment of marine mammal
auditory weighting functions in the new acoustic guidance.
Acoustic Impacts
Please refer to the information given previously (Description of
Sound Sources) regarding sound, characteristics of sound types, and
metrics used in this document. Anthropogenic sounds cover a broad range
of frequencies and sound levels and can have a range of highly variable
impacts on marine life, from none or minor to potentially severe
responses, depending on received levels, duration of exposure,
behavioral context, and various other factors. The potential effects of
underwater sound from active acoustic sources can potentially result in
one or more of the following: Temporary or permanent hearing
impairment, non-auditory physical or physiological effects, behavioral
disturbance, stress, and masking (Richardson et al., 1995; Gordon et
al., 2004; Nowacek et al., 2007; Southall et al., 2007). The degree of
effect is intrinsically related to the signal characteristics, received
level, distance from the source, and duration of the sound exposure. In
general, sudden, high level sounds can cause hearing loss, as can
longer exposures to lower level sounds. Temporary or permanent loss of
hearing will occur almost exclusively for noise within an animal's
hearing range. In this section, we first describe specific
manifestations of acoustic effects before providing discussion specific
to the proposed construction activities in the next section.
Permanent Threshold Shift--Marine mammals exposed to high-intensity
sound, or to lower-intensity sound for prolonged periods, can
experience hearing threshold shift (TS), which is the loss of hearing
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt
et al., 2000; Finneran et al., 2002, 2005). TS can be permanent (PTS),
in which case the loss of hearing sensitivity is not fully recoverable,
or temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Repeated sound exposure that
leads to TTS could cause PTS. In severe cases of PTS, there can be
total or partial deafness, while in most cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals--PTS data exists only for a single harbor seal
(Kastak et al., 2008)--but are assumed to be similar to those in humans
and other terrestrial mammals. PTS typically occurs at exposure levels
at least several decibels above (a 40-dB threshold shift approximates
PTS onset; e.g., Kryter et al., 1966; Miller, 1974) that inducing mild
TTS (a 6-dB threshold shift approximates TTS onset; e.g., Southall et
al., 2007). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulse sounds (such as
impact pile driving pulses as received close to the source) are at
least six dB higher than the TTS threshold on a peak-pressure basis and
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher
than TTS cumulative sound exposure level thresholds (Southall et al.,
2007).
Temporary threshold shift--TTS is the mildest form of hearing
impairment that can occur during exposure to sound (Kryter, 1985).
While experiencing TTS, the hearing threshold rises, and a sound must
be at a higher level in order to be heard. In terrestrial and marine
mammals, TTS can last from minutes or hours to days (in cases of strong
TTS). In many cases, hearing sensitivity recovers rapidly after
exposure to the sound ends.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. 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. 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 occurs during a time where ambient noise is lower and there
are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin [Tursiops trancatus], beluga whale [Delphinapterus
leucas], harbor porpoise, and Yangtze finless porpoise [Neophocoena
asiaeorientalis]) and three species of pinnipeds (northern elephant
seal [Mirounga angustirostris], harbor seal, and California sea lion
[Zalophus californianus]) exposed to a limited number of sound sources
(i.e., mostly tones and octave-band noise) in laboratory settings
(e.g., Finneran et al., 2002; Nachtigall et al., 2004; Kastak et al.,
2005; Lucke et al., 2009; Popov et al., 2011). In general, harbor seals
(Kastak et al., 2005; Kastelein et al., 2012a) and harbor porpoises
(Lucke et al., 2009; Kastelein et al., 2012b) have a lower TTS onset
than other measured pinniped or cetacean species. Additionally, the
existing marine mammal TTS data come from a limited number of
individuals within these species. There are no data available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS in
marine mammals or for further discussion of TTS onset thresholds,
please see Southall et al. (2007), Finneran and Jenkins (2012), and
Finneran (2015).
Behavioral effects--Behavioral disturbance may include a variety of
effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. 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
[[Page 31411]]
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). Please see
Appendices B-C of Southall et al. (2007) for a review of studies
involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. As noted, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2003). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al.; 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et
al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007b). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine
[[Page 31412]]
mammal strandings (Evans and England, 2001). However, it should be
noted that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) 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).
Auditory 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., shipping,
sonar, seismic exploration) in origin. The ability of a 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.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009)
[[Page 31413]]
and may result in energetic or other costs as animals change their
vocalization behavior (e.g., Miller et al., 2000; Foote et al., 2004;
Parks et al., 2007b; Di Iorio and Clark, 2009; Holt et al., 2009).
Masking can be reduced in situations where the signal and noise come
from different directions (Richardson et al., 1995), through amplitude
modulation of the signal, or through other compensatory behaviors
(Houser and Moore, 2014). Masking can be tested directly in captive
species (e.g., Erbe, 2008), but in wild populations it must be either
modeled or inferred from evidence of masking compensation. There are
few studies addressing real-world masking sounds likely to be
experienced by marine mammals in the wild (e.g., Branstetter et al.,
2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
At the seafood processing plant north of the project site, fish are
offloaded into the processing plant from the vessels' holds, and
several vessels may raft up simultaneously during peak fishing seasons.
A small boat harbor is located northeast of the project site and
services a number of small vessels. High levels of vessel traffic are
known to elevate background levels of noise in the marine environment.
For example, continuous sounds for tugs pulling barges have been
reported to range from 145 to 166 dB re 1 [mu]Pa rms at 1 meter from
the source (Miles et al., 1987; Richardson et al., 1995; Simmonds et
al., 2004). Ambient underwater noise levels in the vicinity of the
project site are unknown but could potentially mask some sounds of pile
installation and pile extraction.
Non-auditory physiological effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to strong underwater sound include stress, neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies
examining such effects are limited. In general, little is known about
the potential for pile driving to cause auditory impairment or other
physical effects in marine mammals. Available data suggest that such
effects, if they occur at all, would presumably be limited to short
distances from the sound source, where SLs are much higher, and to
activities that extend over a prolonged period. The available data do
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007) or any
meaningful quantitative predictions of the numbers (if any) of marine
mammals that might be affected in those ways. Marine mammals that show
behavioral avoidance of pile driving, including some odontocetes and
some pinnipeds, are especially unlikely to incur auditory impairment or
non-auditory physical effects.
Underwater Acoustic Effects From the Proposed Activities
Potential Effects of Pile Driving Sound--The effects of sounds from
pile driving might include one or more of the following: Temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, and behavioral disturbance (Richardson et al., 1995; Gordon et
al., 2003; Nowacek et al., 2007; Southall et al., 2007). The effects of
pile driving on marine mammals are dependent on several factors,
including the type and depth of the animal; the pile size and type, and
the intensity and duration of the pile driving sound; the substrate;
the standoff distance between the pile and the animal; and the sound
propagation properties of the environment. Impacts to marine mammals
from pile driving activities are expected to result primarily from
acoustic pathways. As such, the degree of effect is intrinsically
related to the frequency, received level, and duration of the sound
exposure, which are in turn influenced by the distance between the
animal and the source. The further away from the source, the less
intense the exposure should be. The substrate and depth of the habitat
affect the sound propagation properties of the environment. In
addition, substrates that are soft (e.g., sand) would absorb or
attenuate the sound more readily than hard substrates (e.g., rock)
which may reflect the acoustic wave. Soft porous substrates would also
likely require less time to drive the pile, and possibly less forceful
equipment, which would ultimately decrease the intensity of the
acoustic source.
Hearing Impairment and Other Physical Effects--Marine mammals
exposed to high intensity sound repeatedly or for prolonged periods can
experience hearing threshold shifts. PTS constitutes injury, but TTS
does not (Southall et al., 2007). Based on the best scientific
information available, the SPLs for the proposed construction
activities may exceed the thresholds that could cause TTS or the onset
of PTS based on NMFS' new acoustic guidance (81 FR 51694; August 4,
2016).
Non-auditory Physiological Effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to high level underwater sound or as a secondary effect of
extreme behavioral reactions (e.g., change in dive profile as a result
of an avoidance reaction) caused by exposure to sound include
neurological effects, bubble formation, resonance effects, and other
types of organ or tissue damage (Cox et al., 2006; Southall et al.,
2007; Zimmer and Tyack, 2007). The proposed activities do not involve
the use of devices such as explosives or mid-frequency active sonar
that are associated with these types of effects, nor do they have SLs
that may cause these extreme behavioral reactions, and are therefore,
considered unlikely.
Disturbance Reactions--Responses to continuous sound, such as
vibratory pile installation, have not been documented as well as
responses to pulsed sounds. With both types of pile driving, it is
likely that the onset of pile driving could result in temporary, short
term changes in an animal's typical behavior and/or avoidance of the
affected area. Specific behavioral changes that may result from this
proposed project include changing durations of surfacing and dives,
moving direction and/or speed; 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. If a marine
mammal responds to a stimulus by changing its behavior (e.g., through
relatively minor changes in locomotion direction/speed or vocalization
behavior), the response may or may not constitute taking at the
individual level, and is unlikely to affect the stock or the species as
a whole. However, if a sound source displaces marine mammals from an
important feeding or breeding area for a prolonged period, potential
impacts on the stock or species could potentially be significant if
growth, survival and reproduction are affected (e.g., Lusseau and
Bejder, 2007; Weilgart, 2007). Note that the significance of many of
these behavioral disturbances is difficult to predict, especially if
the detected disturbances appear minor.
[[Page 31414]]
Auditory Masking--Natural and artificial sounds can disrupt
behavior by masking. Given that the energy distribution of pile driving
covers a broad frequency spectrum, sound from these sources would
likely be within the audible range of marine mammals present in the
project area. Impact pile driving activity is relatively short-term,
and only used for proofing, with rapid pulses occurring for only a few
minutes per pile. The probability for impact pile driving resulting
from this proposed action masking acoustic signals important to the
behavior and survival of marine mammal species is low. Vibratory pile
driving is also relatively short-term. It is possible that vibratory
pile driving resulting from this proposed action may mask acoustic
signals important to the behavior and survival of marine mammal
species, but the short-term duration and limited affected area would
result in insignificant impacts from masking. Any masking event that
could possibly rise to Level B harassment under the MMPA would occur
concurrently within the zones of behavioral harassment already
estimated for vibratory and impact pile driving, and which have already
been taken into account in the exposure analysis.
Airborne Acoustic Effects from the Proposed Activities--Pinnipeds
that occur near the project site could be exposed to airborne sounds
associated with pile driving that have the potential to cause
behavioral harassment, depending on their distance from pile driving
activities. Cetaceans are not expected to be exposed to airborne sounds
that would result in harassment as defined under the MMPA.
Airborne noise will primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria. We recognize that
pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with heads above water.
Most likely, airborne sound would cause behavioral responses similar to
those discussed above in relation to underwater sound. However, these
animals would previously have been ``taken'' as a result of exposure to
underwater sound above the behavioral harassment thresholds, which are
in all cases larger than those associated with airborne sound. Thus,
the behavioral harassment of these animals is already accounted for in
these estimates of potential take. Multiple instances of exposure to
sound above NMFS' thresholds for behavioral harassment are not believed
to result in increased behavioral disturbance, in either nature or
intensity of disturbance reaction. Therefore, we do not believe that
authorization of incidental take resulting from airborne sound for
pinnipeds is warranted, and airborne sound is not discussed further
here.
Potential Pile Driving Effects on Prey--Construction activities
would produce continuous (i.e., vibratory pile driving) sounds and
pulsed (i.e., impact driving) sounds. Fish react to sounds that are
especially strong and/or intermittent low-frequency sounds. Short
duration, sharp sounds can cause overt or subtle changes in fish
behavior and local distribution. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fish, although several are based on studies in support of
large, multiyear bridge construction projects (e.g., Scholik and Yan,
2001, 2002; Popper and Hastings, 2009). Sound pulses at received levels
of 160 dB may cause subtle changes in fish behavior. SPLs of 180 dB may
cause noticeable changes in behavior (Pearson et al., 1992; Skalski et
al., 1992). SPLs of sufficient strength have been known to cause injury
to fish and fish mortality.
The most likely impact to fish from pile driving activities at the
project area would be temporary behavioral avoidance. 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. In general, impacts to marine mammal prey species from the
proposed project are expected to be minor and temporary due to the
relatively short timeframe of no more than 40 days of pile driving and
extraction with approximately 22 hours of impact driving and 85 hours
of vibratory driving and extraction.
Effects to Foraging Habitat--Essential Fish Habitat (EFH) has been
designated within the project area for all five species of salmon
(i.e., chum, pink, Coho, sockeye, and Chinook salmon), walleye pollock,
Pacific cod, yellowfin sole (Limanda aspera), arrowtooth flounder
(Atheresthes stomias), rock sole (Lepidopsetta spp.), flathead sole
(Hippoglossoides elassodon), and sculpin (Cottidae). The EFH provisions
of the Magnuson-Stevens Fishery Conservation and Management Act are
designed to protect fisheries habitat from being lost due to
disturbance and degradation.
Pile installation may temporarily increase turbidity resulting from
suspended sediments. Any increases would be temporary, localized, and
minimal. ADOT&PF must comply with state water quality standards during
these operations by limiting the extent of turbidity to the immediate
project area. In general, turbidity associated with pile installation
is localized to about a 25-foot radius around the pile (Everitt et al.
1980). Cetaceans are not expected to be close enough to the project
pile driving areas to experience effects of turbidity, and any
pinnipeds will be transiting the area and could avoid localized areas
of turbidity. Therefore, the impact from increased turbidity levels is
expected to be discountable to marine mammals. Furthermore, pile
driving and removal at the project site will not obstruct movements or
migration of marine mammals.
In summary, given the short duration of sound associated with
individual pile driving events and the relatively small area that would
be 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. Thus, any impacts to marine
mammal habitat are not expected to cause significant or long-term
consequences for individual marine mammals or their populations.
Estimated Take
This section includes an estimate of the number of incidental
``takes'' proposed for authorization pursuant to this IHA, which will
inform both NMFS' consideration of whether the number of takes is
``small'' and the negligible impact determination.
Harassment is the only means of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, 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]. As described previously Level A and
Level B harassment is expected to occur and is proposed to be
authorized in the numbers identified below.
ADOT&PF has requested authorization for the incidental taking of
limited numbers, by Level B harassment in the form of behavioral
disturbance, of harbor porpoise, Dall's porpoise, killer whale,
humpback whale, fin whale, gray whale, minke whale, Steller sea lion,
[[Page 31415]]
and harbor seal near the project area that may result from impact and
vibratory pile driving activities. Level A harassment in the form of
PTS resulting from impact driving has also been requested for small
numbers of harbor porpoise, humpback whale, and harbor seal.
Take estimates are generally based on average marine mammal density
in the project area multiplied by the area size of ensonified zones
within which received noise levels exceed certain thresholds (i.e.,
Level A and/or Level B harassment) from specific activities, then
multiplied by the total number of days such activities would occur. If
density information is not available, local observational data may be
used instead.
In order to estimate the potential incidents of take that may occur
incidental to the specified activity, we must first estimate the extent
of the sound field that may be produced by the activity and then
consider the sound field in combination with information about marine
mammal density or abundance in the project area. We first provide
information on applicable sound thresholds for determining effects to
marine mammals before describing the information used in estimating the
sound fields, the available marine mammal density or abundance
information, and the method of estimating potential incidents of take.
Sound Thresholds
We use the following generic sound exposure thresholds (Table 4) to
determine when an activity that produces sound might result in impacts
to a marine mammal such that a take by behavioral harassment (Level B)
might occur.
Table 4--Underwater Level B Threshold Decibel Levels for Marine Mammals
------------------------------------------------------------------------
Criterion Criterion definition Threshold \1\
------------------------------------------------------------------------
Level B harassment............ Behavioral disruption 160 dB RMS.
for impulse noise
(e.g., impact pile
driving).
Level B harassment............ Behavioral disruption 120 dB RMS.
for non-pulse noise
(e.g., vibratory pile
driving, drilling).
------------------------------------------------------------------------
\1\ All decibel levels referenced to 1 micropascal (re: 1 [mu]Pa). Note
all thresholds are based off root mean square (RMS) levels.
We use NMFS' acoustic criteria (NMFS 2016a, 81 FR 51694; August 4,
2016), which establishes sound exposure thresholds to determine when an
activity that produces sound might result in impacts to a marine mammal
such that a take by auditory injury, i.e., PTS, (Level A harassment)
might occur. The specific methodology is presented in Appendix D of the
Technical Guidance for Assessing the Effects of Anthropogenic Sound on
Marine Mammal Hearing (Guidance), available at http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm) and the accompanying
User Spreadsheet. The Guidance provides updated PTS onset thresholds
using the cumulative SEL (SELcum) metric, which incorporates
marine mammal auditory weighting functions, to identify the received
levels, or acoustic thresholds, at which individual marine mammals are
predicted to experience changes in their hearing sensitivity for acute,
incidental exposure to all underwater anthropogenic sound sources. The
Guidance (Appendix D) and its companion User Spreadsheet provide
alternative methodology for incorporating these more complex thresholds
and associated weighting functions.
The User Spreadsheet accounts for effective hearing ranges using
Weighting Factor Adjustments (WFAs), and ADOT&PF's application uses the
recommended values for vibratory and impact driving therein. The
acoustic thresholds are presented using dual metrics of
SELcum and peak sound level (PK) as shown in Table 5. In the
case of the duel metric acoustic thresholds (Lpk and
LE) for impulsive sound, the larger of the two isopleths for
calculating PTS onset is used. The method uses estimates of sound
exposure level and duration of the activity to calculate the threshold
distances at which a marine mammal exposed to those values would
experience PTS. Differences in hearing abilities among marine mammals
are accounted for by use of weighting factor adjustments for the five
functional hearing groups (NMFS 2016). Note that for all proposed pile
driving activities at Sand Point, the User Spreadsheet indicated that
the Level A isopleths generated using the SELcum were the
largest.
Table 5--Summary of PTS Onset Acoustic Thresholds
------------------------------------------------------------------------
PTS onset acoustic thresholds \1\
(received level)
Hearing group ---------------------------------------
Impulsive Non-impulsive
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.... Cell 1--Lpk,flat: Cell 2--LE,LF,24h:
219 dB; 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans.... Cell 3--Lpk,flat: Cell 4--LE,MF,24h:
230 dB; 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans... Cell 5--Lpk,flat: Cell 6--LE,HF,24h:
202 dB; 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) Cell 7--Lpk,flat: Cell 8--LE,PW,24h:
(Underwater). 218 dB; 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) Cell 9--Lpk,flat: Cell 10--
(Underwater). 232 dB; LE,OW,24h: 219
LE,OW,24h: 203 dB. dB.
------------------------------------------------------------------------
\1\ Dual metric acoustic thresholds for impulsive sounds: Use whichever
results in the largest isopleth for calculating PTS onset. If a non-
impulsive sound has the potential of exceeding the peak sound pressure
level thresholds associated with impulsive sounds, these thresholds
should also be considered.
[[Page 31416]]
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and
cumulative sound exposure level (LE) has a reference value of
1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect
American National Standards Institute standards (ANSI 2013). However,
peak sound pressure is defined by ANSI as incorporating frequency
weighting, which is not the intent for this Technical Guidance. Hence,
the subscript ``flat'' is being included to indicate peak sound
pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure
level thresholds indicates the designated marine mammal auditory
weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The
cumulative sound exposure level thresholds could be exceeded in a
multitude of ways (i.e., varying exposure levels and durations, duty
cycle). When possible, it is valuable for action proponents to
indicate the conditions under which these acoustic thresholds will be
exceeded.
Distance to Sound Thresholds
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, vibratory
pile driving, and vibratory pile removal. Vibratory hammers produce
constant sound when operating, and produce vibrations that liquefy the
sediment surrounding the pile, allowing it to penetrate to the required
seating depth. An impact hammer would then generally be used to place
the pile at its intended depth. The actual durations of each
installation method vary depending on the type and size of the pile. An
impact hammer is a steel device that works like a piston, producing a
series of independent strikes to drive the pile. Impact hammering
typically generates the loudest noise associated with pile
installation. Factors that could potentially minimize the potential
impacts of pile installation associated with the project include:
The relatively shallow waters in the project area (Taylor
et al., 2008);
Land forms around Sand Point that would block the noise
from spreading; and
Vessel traffic and other commercial and industrial
activities in the project area that contribute to elevated background
noise levels.
Sound would likely dissipate relatively rapidly in the shallow
waters over soft seafloors in the project area. Additionally, portions
of Popof Island and Unga Island would block much of the noise from
propagating to its full extent through the marine environment.
In order to calculate distances to the Level A and Level B sound
thresholds for piles of various sizes being used in this project, NMFS
used acoustic monitoring data from other locations. Note that piles of
differing sizes have different sound source levels.
Empirical data from recent ADOT&PF sound source verification (SSV)
studies at Kake, Ketchikan, and Auke Bay, were used to estimate sound
source levels (SSLs) for vibratory and impact installation of 30-inch
steel pipe piles (MacGillivray et al., 2016, Warner and Austin 2016b,
Denes et al., 2016a, respectively). Construction sites in Alaska were
generally assumed to best represent the environmental conditions found
in Sand Point and represent the nearest available source level data for
30-inch steel piles. Similarities among the sites include island chains
and groups of islands adjacent to continental landmasses; deeply
incised marine channels and fjords; local water depths of 20-40 meters;
Gulf of Alaska marine water influences; and numerous freshwater inputs.
However, the use of data from Alaska sites was not appropriate in all
instances. Details are described below.
To derive source levels for vibratory driving of 30-in piles, NMFS
used summary data from Auke Bay and Ketchikan as described in a
comprehensive summary report by Denes et al., (2016b). During the two
studies, three 30-inch steel piles were installed at each location via
both impact and vibratory driving. For each pile, the mean recorded SPL
in dB re 1 [mu]Pa was reported for the locations monitoring hydrophones
(Denes et al., 2016; Warner and Austin 2016b). The vibratory data were
then derived to a 10-meter standard distance. The average of the mean
source levels from both Auke Bay and Ketchikan locations was then
calculated for each measurement (rms and peak SPL, as well as sound
exposure level [SEL]) (Denes et al., 2016b). ADOT&PF also considered
data from a study in Kake (MacGillivray et al., 2016). However,
conditions at Kake include an organic mud substrate which would likely
absorb sound and decrease source level values for vibratory driving.
NMFS believes that these conditions resulted in anomalous source level
measurements for vibratory pile driving that would not be expected at
locations with dissimilar substrates. NMFS will continue to evaluate
use of these data on a case-specific basis, however, for these reasons
vibratory data from that study was not included in this analysis.
Results are shown in Table 6.
For vibratory driving of 24-inch steel dolphin and fender piles,
data from three projects (two projects in Washington and one in
California) were reviewed. The Washington marine projects at the
Washington State Ferries Friday Harbor Terminal (WSDOT, 2010) and Naval
Base Kitsap, Bangor waterfront (Navy 2012), only measured one pile
each, but reported similar sound levels of 162 dB RMS and 159 dB RMS
(range 157 dB to 160 dB), respectively. Because only two piles were
measured in Washington, the California project was also included in the
analysis. The California project was located in a coastal bay and
reported a ``typical'' value of 160 dB RMS with a range 158 to 178 dB
RMS for two piles where vibratory levels were measured. Caltrans
summarized the project's RMS level as 170 dB RMS, although most levels
observed were nominally 160 dB. Although the data set is limited to
these projects, close agreement of the levels (average project values
from 159 to 162 dB at 10 meters) resulted in NMFS selecting a source
level of 161 dB RMS. Note that a fourth project at NBK, Bangor drove
16-inch hollow steel piles, with measured levels similar to those for
the 24-inch piles. Therefore, NMFS elected to use the same 161 dB RMS
as a source level for vibratory driving of 18-inch steel piles. NMFS
believes it appropriate to use source levels from the next largest pile
size when data are lacking for specific pile sizes, as is the case with
the18-inch piles under consideration.
ADOT&PF suggested a source level of 142 dB RMS for vibratory
driving of steel H-piles. However, NMFS found this data to be
inconsistent with other reported values and opted to use a value of 150
dB which was derived from summary data pertaining to vibratory driving
of 12-inch H piles (Caltrans 2015).
In the application, ADOT&PF derived source levels for impact
driving of 30-inch steel piles by averaging the individual mean values
associated with impact driving of the same size and type from Auke Bay,
Kake, and Ketchikan (Denes et al., 2016a; MacGillivray et al., 2016;
Warner and Austin 2016b; Denes et al., 2016b). Impact driving values at
Kake did not seem to be influenced by substrate conditions in the way
vibratory driving measurements are believed to have been and,
therefore, Kake data was included. The average of the mean source
levels from these three sites was then calculated for each metric (rms,
SEL, and peak). Results are shown in Table 6.
[[Page 31417]]
For the 24-inch impact pile driving, NMFS used data from a Navy
(2015) study of proxy sound source values for use at Puget Sound
military installations. The Navy study recommended a value of 193 dB
RMS which was derived from data generated by impact driving of 24-inch
steel piles at the Bainbridge Island Ferry Terminal Preservation
Project and the Friday Harbor Restoration Ferry Terminal Project. NMFS
found this estimated source level to be appropriate.
Table 6--Estimates of Mean Underwater Sound Levels (Decibels) Generated During Vibratory and Impact Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Method and pile type Sound level at 10 meters
--------------------------------------------------------------------------------------- Literature source
Vibratory hammer dB re 1 [mu]Pa rms
----------------------------------------------------------------------------------------------------------------
30-inch steel piles................... 165.6 Derived from Denes et
al. 2016a (Auke);
Warner and Austin 2016b
(Ketchikan).
24-inch steel piles................... 161 WSDOT 2010; Caltrans
2012; Navy 2012.
18-inch steel piles................... 161 WSDOT 2010; Caltrans
2012; Navy 2012.
Steel H-piles......................... 150 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
Impact hammer dB rms dB SEL dB peak
----------------------------------------------------------------------------------------------------------------
30-inch steel piles................... 193.6 179.3 207.1 Derived from Denes et
al. 2016a; Warner and
Austin 2016b,
MacGillivray et al.,
2016.
24-inch steel piles................... 193 181 210 Navy 2015.
----------------------------------------------------------------------------------------------------------------
The formula below is used to calculate underwater sound
propagation. Transmission loss (TL) is the decrease in acoustic
intensity as an acoustic pressure wave propagates out from a source. TL
parameters vary with frequency, temperature, sea conditions, current,
source and receiver depth, water depth, water chemistry, and bottom
composition and topography. The general formula for underwater TL is:
TL = B * log 10 (R 1/R 2)
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R 1 = the distance of the modeled SPL from the driven
pile, and
R 2 = the distance from the driven pile of the initial
measurement.
NMFS typically recommends a default practical spreading loss of 15
dB per tenfold increase in distance. ADOT&PF analyzed the available
underwater acoustic data utilizing the practical spreading loss model.
Pulse duration from the SSV studies described above are unknown.
All necessary parameters were available for the SELcum (cumulative
Single Strike Equivalent) method for calculating isopleths. Therefore,
this method was selected. To account for potential variations in daily
productivity during impact installation, isopleths were calculated for
different numbers of piles that could be installed each day (Table 7).
Should the contractor expect to install fewer piles in a day than the
maximum anticipated, a smaller Level A shutdown zone would be employed
to monitor take.
To derive Level A harassment isopleths associated with the impact
driving of 30-inch piles, ADOT&PF utilized a single strike SEL of 179.3
dB and assumed 1000 strikes per pile for 1 to 4 piles per day. For 24-
inch dolphin piles, ADOT&PF used a single strike SEL of 181 dB and
assumed 400 strikes at a rate of 1 or 2 piles per day. For 24-inch
fender piles, ADOT&PF used the same single strike SEL of 181 dB and
assumed 120 strikes per pile and 1 to 4 pile installations per day. To
calculate Level A harassment isopleths associated with the vibratory
driving of 30-inch piles, ADOT&PF utilized a source level (RMS SPL) of
165.6 dB and assumed 3 hours of driving per day. For 24-inch dolphin
and fender piles, ADOT&PF used a source level of 161 dB and assumed up
to 2 hours of driving per day. For installation and/or removal of piles
less than 24-inches in diameter, ADOT&PF assumed use of 18-inch piles
and used the same source level of 161 dB for up to 3 hours per day. If
H-piles are used, a source level of 150 dB was utilized. Practical
spreading was used in all instances. Results are shown in Table 7.
Isopleths for Level B harassment associated with impact (160 dB) and
vibratory harassment (120 dB) were also calculated and are included in
Table 7.
Table 7--Pile Installation and Removal Activities and Calculated Distances to Level A and Level B Harassment Isopleths \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated duration Level A harassment zone (meters) (based on new Level B
---------------------- technical guidance) Harassment Zone
------------------------------------------------------- (meters) (based
Cetaceans Pinnipeds on practical
------------------------------------------------------- spreading loss
Activity Hours per Days of model)
day effort -----------------
LF MF HF PW OW Cetaceans and
Pinnipeds (120
dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation 30''.............................. 3 13 28.8 2.6 42.6 17.5 1.2 10,970 (10,964)
Vibratory Installation 24'' Dolphin...................... 1 2 6.8 0.6 10.1 4.2 0.3
Vibratory Installation 24'' Fender....................... 2 2 10.8 1 16 6.6 0.5 5,420 (5,412)
Vibratory Installation and/or removal <24'' (18'')....... 3 15 14 1 21 8.6 0.6
[[Page 31418]]
Vibratory Installation and/or removal <24'' (H-piles).... 3 15 2.6 0.2 3.9 1.6 0.1 1,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetaceans Pinnipeds Cetaceans and
Activity Piles per Strikes Days of ------------------------------------------------------- Pinnipeds (160
day per pile effort LF MF HF PW OW dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation 30''...................... 4 1,000 13 1,426 51 1,699 763 56 1,740 (1,738)
3 18 1,177 42 1,402 630 46
2 26 898 32 1,070 481 35
1 52 566 20 674 303 22
Impact Installation 24'' Dolphin.............. 2 400 2 633 23 754 339 25
1 3 399 14 475 213 16
Impact Installation 24'' Fender............... 4 120 2 450 16 537 241 18 1,590 (1,585)
3 3 372 13 443 199 15
2 4 284 10 338 152 11
1 8 178 6 213 96 7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ To account for potential variations in daily productivity during impact installation, isopleths were calculated for different numbers of piles that
could be installed each day (Therefore, should the contractor expect to install fewer piles in a day than the maximum anticipated, a smaller Level A
shutdown zone would be required to avoid take.)
Note that the actual area ensonified by pile driving activities is
significantly constrained by local topography relative to the total
threshold radius. The actual ensonified area was determined using a
straight line-of-sight projection from the anticipated pile driving
locations. The corresponding areas of the Level A and Level B
ensonified zones for impact driving and vibratory installation/removal
are shown in Table 8.
Table 8--Calculated Areas (km\2\) Ensonified Within Level A and Level B Harassment Thresholds in Excess of 100-Meter Distance During Pile Installation
and Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated duration Level A harassment zone (km\2\) (based on new Level B
---------------------- technical guidance) harassment zone
------------------------------------------------------- (km\2\) (based
Cetaceans Pinnipeds on practical
------------------------------------------------------- spreading loss
Activity Hours per Days of model)
day effort -----------------
LF MF HF PW OW Cetaceans and
Pinnipeds (120
dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation 30''.............................. 3 13 NA NA NA NA NA 24.42
Vibratory Installation 24'' Dolphin...................... 1 2 NA NA NA NA NA 17.19
Vibratory Installation 24'' Fender....................... 2 2 NA NA NA NA NA
Vibratory Installation and/or removal <24'' (18'')....... 3 15 NA NA NA NA NA
Vibratory Installation and/or removal <24'' (H-piles).... 3 15 NA NA NA NA NA 1.47
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetaceans Pinnipeds Cetaceans and
Activity Piles per Strikes Days of ------------------------------------------------------- Pinnipeds (160
day per pile effort LF MF HF PW OW dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation 30''...................... 4 1,000 13 2.84 NA 3.91 0.91 NA 4.08
3 18 1.98 NA 2.75 0.66 NA
2 26 1.21 NA 1.66 0.41 NA
1 52 0.55 NA 0.74 0.18 NA
Impact Installation 24'' Dolphin.............. 2 400 2 0.67 NA 0.89 0.22 NA 3.45
1 3 0.29 NA 0.40 0.09 NA
[[Page 31419]]
Impact Installation 24'' Fender............... 4 120 2 0.36 NA 0.50 0.11 NA
3 3 0.26 NA 0.35 0.08 NA
2 4 0.16 NA 0.22 0.04 NA
1 8 0.06 NA 0.09 0.02 NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Potential exposures to impact and vibratory pile driving noise for
each threshold were estimated using local marine mammal density
datasets where available and local observational data.
Dall's Porpoise
There currently is no information on the presence or abundance of
Dall's porpoises in the Shumagin Islands. No sightings of Dall's
porpoises have been documented in Humboldt Harbor and they are not
expected to occur there (HDR 2017). However, individuals may occur in
the deeper waters north of Popof Island or in Popof Strait, west of the
Sand Point Airport. These porpoises have been sighted infrequently on
research cruises heading in and out of Sand Point in deeper local
waters (Speckman, Pers. Comm.). Dall's porpoise are non-migratory;
therefore, exposure estimates are not dependent on season. Exposure of
Dall's porpoise to noise from impact hammer pile installation is
unlikely, as they are not expected to occur within the 1,738 meter
Level B harassment zone. Similarly, we do not anticipate Dall's
porpoise would be exposed to noise in excess of the Level A harassment
threshold, which would be located at a maximum distance of 1,699
meters. It is possible, however, that they would occur in the larger
Level B zone associated with vibratory driving of 30-inch (up to 10,970
meters) and 24-inch piles (up to 5,420 meters). Over the course of 40
days in which vibratory driving will be employed, NMFS conservatively
anticipates no more than one observation of a Dall's porpoise pod in
these Level B vibratory harassment zones. With an average pod size of
3.7 (Wade et al. 2003), NMFS estimates up to four Dall's porpoises
could be taken during the pile installation period. No Level A take is
proposed for Dall's porpoises.
Harbor Porpoise
There are no reports of harbor porpoises or harbor porpoise
densities in the Shumagin Islands. It is reasonable to assume that they
would occur in the vicinity of Popof and Unga Islands given that they
are common in the Gulf of Alaska and their preferred habitat consists
of coastal waters of 100 meters or less (Hobbs and Waite 2010). Based
on the known range of the Gulf of Alaska stock, only six sightings of
singles or pairs during 110 days of monitoring of the Kodiak Ferry
Terminal and Dock Improvements project, and occasional sightings during
monitoring of projects at other locations on Kodiak Island, it is
assumed that harbor porpoises could be present on an intermittent
basis.
Harbor porpoises are non-migratory; therefore, exposure estimates
are not dependent on season. NMFS conservatively estimates harbor
porpoise could be exposed to construction-related in-water noise on two
out of every three construction days. Harbor porpoises in this area
have an average group size of 1.82. Therefore, NMFS estimates 49 harbor
porpoise exposures as shown below.
Sighting every 0.667 days * 40 days of exposure * 1.82 group size =
49 (48.55) rounded up).
During impact installation of piles, the Level A harassment
isopleth for harbor porpoises extends up to 1,699 meters when a maximum
of four 30-inch piles are installed on the same day. Given that harbor
porpoises prefer near-shore waters, we anticipate that it is possible
for up to one-third of the harbor porpoise sighting to occur in a Level
A harassment zone. Therefore, NMFS proposes that of the 49 exposures,
16 will occur within a Level A harassment isopleth and 33 will occur
within a Level B harassment isopleth.
Killer Whale
Line transect surveys conducted in the Shumagin Islands between
2001 and 2003 did not record any resident killer whales, but did record
a relatively high abundance of transient killer whales (Zerbini et al.,
2007). The same study estimated a density of approximately 0.002 killer
whales per square kilometer (km\2\) in the Shumagin Islands (Zerbini et
al., 2007). The population trend of the transient stock of killer
whales in Alaska has remained stable since the 1980s (Muto et al.,
2016a). Anecdotal observations indicate that killer whales are not
often seen in the vicinity of Sand Point, including Popof Strait (HDR
2017). Killer whales are expected to be uncommon in the project area
and are not expected to enter into Humboldt Harbor. However, NMFS used
the density estimate of 0.002 per km\2\ to determine the number of
killer whales potentially observed within the project area. Given the
low probability of occurrence within the project area, using the
available density estimates as an indication of exposure is a
conservative approach to estimate potential killer whale exposure to
pile driving noise. Vibratory installation of 30-inch piles will occur
on 13 days while vibratory installation of 24-inch dolphin piles, 24-
inch fender piles, and temporary 18-inch or h-piles will occur on a
total of 19 days. NMFS assumed that 18-inch piles would be installed
instead of h-piles and that 18-inch piles have the same source level
and isopleth as 24-in piles. NMFS also added a 25 percent contingency
factor to account for unanticipated delays. Therefore, there would be
up to 16.25 days of vibratory installation of 30-inch piles and 23.75
days of 24-inch piles. At a density of 0.002 whales/km\2\, NMFS
anticipates approximately 0.79 killer whales (i.e., 0.002 whales/km\2\
* 24.42 km\2\ 30-inch vibratory harassment zone * 16.25 days) would be
exposed to Level B harassment associated with 30-inch vibratory driving
while 0.82 killer whales (i.e., 0.002 whales/km\2\ * 17.19 km\2\ 24-
inch vibratory harassment zone * 23.75 days) would be exposed to Level
B harassment from 24-inch vibratory driving over 40 days. Over the 40
day construction period, 2 killer whales (1.61 rounded up) would be
exposed to Level B harassment.
However, killer whales generally travel in pods, or groups of
individuals. The average pod size for transient killer whales is four
individuals (Zerbini et al. 2007) and 5-50 for resident killer whales
(Heise et al. 2003). A monitoring report associated with issuance of an
IHA for Kodiak Ferry Terminal and Dock Improvements Project recorded
four killer whale pod observations during 110 days of monitoring with
the largest pod size consisting of seven individuals. NMFS will,
therefore, assume that there will be sightings of two pods with an
average group size of
[[Page 31420]]
seven over the course of the 40-day construction period resulting in a
total estimate of 14 killer whale Level B takes. These killer whales
would likely be transients, but could also be residents, so take is
proposed for both stocks. No Level A take is proposed for killer whales
since the injury zone is smaller than the 100 meter shutdown zone.
Humpback Whale
Surveys from 2001 to 2004 estimated humpback whale abundance in the
Shumagin Islands at between 410 and 593 individuals during the summer
feeding season (July-August; Witteveen et al., 2004; Zerbini et al.,
2006). Annual vessel-based, photo-identification surveys in the
Shumagin Islands from 1999 to 2015 identified 654 unique individual
humpback whales between June and September (Witteveen and Wynne 2016).
Humpback whale abundance in the Shumagin Islands increased 6 percent
per year between 1987 and 2003 (Zerbini et al., 2006). Between 2001 and
2003, summer line transect surveys in the Shumagin Islands estimated
the humpback whale density at 0.02 whales per km\2\ (Zerbini et al.,
2006). Given an approximate population increase of 6 percent each year
since the early 2000's (Muto et al., 2016b), we conservatively estimate
the current density of humpback whales as about 0.04 whale per km\2\
(0.02 whale/km\2\ * [6 percent increase/year * 13 years]).
Exposure of humpback whales to Level A and Level B harassment noise
levels is possible in August and, to a lesser extent, in September.
Exposure is unlikely between October and December because humpback
whale abundance is low during late fall and winter. Humpback whales,
when present, are unlikely to enter Humboldt Harbor or approach the
City of Sand Point, but would instead transit through Popof Strait or
feed in the deeper waters off the airport, between Popof and Unga
islands (HDR 2017). Harassment from pile installation is possible in
waters between Popof and Unga islands, including Popof Strait. Because
we do not know exactly when construction might occur, we will use the
updated summer density estimate (and our only density estimate) of 0.04
whales/km\2\ to estimate exposure.
At a density of 0.04 whales/km\2\, NMFS anticipates approximately
15.87 humpback whales (i.e., 0.04 whales/km\2\ * 24.42 km\2\ 30-inch
vibratory harassment zone * 16.25 days) would be exposed to harassment
on days when 30-inch vibratory driving would occur. Additionally, 16.33
whales (i.e., 0.04 whales/km\2\ * 17.19 km\2\ 24-inch vibratory
harassment zone * 23.75 days) would be exposed to harassment on days in
which 24-inch piles are driven for a total of 32 (32.2 rounded down)
whale takes over 40 days.
A subset of the 32 humpback whales potentially exposed to
harassment noise levels may enter the Level A harassment zone, which
extends 1,426 meters assuming an optimal productivity of driving four
30-inch piles per day; 633 meters when driving two 24-inch dolphins;
and 450 meters when driving four 24-inch fenders. NMFS has again added
a 25 percent contingency and will assume 16.25 days of 30-inch impact
pile driving, 2.5 days of 24-inch dolphin installation and 2.5 days of
24-inch fender installation. Note that when estimating Level A take,
NMFS conservatively defaulted to the Level A isopleth and corresponding
area associated with maximum number of piles that can driven each day
for each pile size. We anticipate approximately 1.84 humpback whales
(e.g., 0.04 whales/km\2\ * 2.84 km\2\ Level A harassment zone * 16.25
days) would be exposed to Level A harassment during 30-inch impact pile
driving; approximately 0.07 humpback whales (e.g., 0.04 whales/km\2\ *
0.67 km\2\ Level A harassment zone * 2.5 days) would be exposed to
Level A harassment during 24-inch dolphin installation; and
approximately 0.04 humpback whales (e.g., 0.04 whales/km\2\ * 0.36
km\2\ Level A harassment zone * 2.5 days) would be exposed to Level A
harassment during 24-inch fender installation. Therefore, a total of 2
(1.95 rounded up) humpback whales could be exposed to Level A
harassment. Therefore, NMFS is proposing 30 Level B and 2 Level A
humpback whale takes.
Humpback whales found in the Shumagin Islands are predominantly
members of the Hawaii DPS, which are not listed under the ESA. However,
based on a comprehensive photo-identification study, members of both
the Western North Pacific DPS (ESA-listed as endangered) and Mexico DPS
(ESA-listed as threatened) are known to occur in the Gulf of Alaska and
Aleutian Islands. Members of different DPSs are known to intermix on
feeding grounds; therefore, all waters off the coast of Alaska should
be considered to have ESA-listed humpback whales. According to Wade et
al., (2016), the probability of encountering a humpback whale from the
Western North Pacific DPS in the Gulf of Alaska is 0.5 percent (CV
[coefficient of variation] = 0.001). The probability of encountering a
humpback whale from the Mexico DPS is 10.5 percent (CV = 0.16). The
remaining 89 percent (CV = 0.01) of individuals in the Gulf of Alaska
are likely members of the Hawaii DPS (Wade et al., 2016). Therefore it
is estimated that 28 humpback whales would be from the Hawaii DPS,
three humpback whales would be from the threatened Mexico DPS, and 1
humpback whale would be from the endangered Western North Pacific DPS.
Given the small number of anticipated Level A takes, NMFS will assume
that both authorized Level A takes represent members of the Hawaii DPS.
Fin Whale
Vessel-based line-transect surveys of coastal waters between
Resurrection Bay and the central Aleutian Islands were completed in
July and August from 2001 to 2003. Large concentrations of fin whales
were found in the Semidi Islands, located midway between the Shumagin
Islands and Kodiak Island just south of the Alaska Peninsula. The
abundance of fin whales in the Shumagin Islands ranged from a low
estimate of 604 in 2003 to a high estimate of 1,113 in 2002. The
estimated density of fin whales in the Shumagin Islands was 0.007
whales per km\2\ and this is the density estimate assumed for the
project area (Zerbini et al., 2006). Fin whale density in the Shumagin
Islands at other times of the year is unknown, and they are uncommon in
Humboldt Harbor or Popof Strait (HDR 2017). At a density of 0.007
whales/km\2\, NMFS anticipates approximately 2.77 fin whales (i.e.,
0.007 whales/km\2\ * 24.42 km\2\ 30-inch vibratory harassment zone *
16.25 days) would be exposed to Level B harassment on days when 30-inch
vibratory driving would occur. Additionally, 2.86 whales (i.e., 0.007
whales/km\2\ * 17.19 km\2\ 24-inch vibratory harassment zone * 23.75
days) would be exposed to Level B harassment on days in which 24-inch
piles are driven for a total of 6 (5.63 rounded up) Level B takes of
fin whales over 40 days. Therefore, NMFS is proposing 6 Level B fin
whale takes. Fin whales are typically found in deep, offshore waters so
no Level A take is proposed for this species.
Minke Whale
There are no population estimates for minke whales in Alaska;
however, nearshore aerial surveys of the western Gulf of Alaska took
place between 2001 and 2003. These surveys estimated the minke whale
population in that area at approximately 1,233 individuals (Zerbini et
al. 2006). Conservatively, minke whales could be exposed to
construction-related noise levels year round. Surveys indicate a
density of
[[Page 31421]]
0.001 minke whales per km\2\ south of the Alaska Peninsula (including
the Shumagin Islands). At a density of 0.001 whales/km\2\, NMFS
anticipates approximately 0.40 minke whales (i.e., 0.001 whales/km\2\ *
24.42 km\2\ 30-inch vibratory harassment zone * 16.25 days) would be
exposed to Level B harassment on days when 30-inch vibratory driving
would occur. Additionally, 0.41 whales (i.e., 0.001 whales/km\2\ *
17.19 km\2\ 24-inch vibratory harassment zone * 23.75 days) would be
exposed to Level B harassment on days in which 24-inch piles are driven
for a total of 1 (0.81 rounded up) level B take of minke whales over 40
construction days. With a pod size of two or three (NMFS 2015), NMFS
proposes that three minke whales could be taken during the 40-day
construction period. No Level A take is proposed for minke whales due
to low abundance near the project area.
Gray Whale
Gray whales could potentially migrate through the area between
March through May and November through January. Gray whale presence
near Sand Point and in Humboldt Harbor is rare and unlikely to occur
during the construction period. As such, exposure of gray whales to
noise from impact hammer pile installation is unlikely, as they are not
expected to occur within the 1,426 meter harassment zone. Harassment
from vibratory pile installation is possible in the deeper water north
of Popof Strait. Because there are no density estimates for the area
and the rarity of gray whales within the project area, NMFS
conservatively estimates that gray whales will not be observed more
than one time during the construction period. Multiplying the one
potential observation by the average pod size of 2.4 (Rugh et al.,
2005), NMFS estimates that two gray whales could be exposed to
construction-related noise at the Level B harassment level over the
course of the construction period. No Level A take is proposed for gray
whales.
Steller Sea Lion
The number of unique individuals used to calculate take was based
on information reported by the nearby seafood processing facility. It
is estimated that about 12 unique individual sea lions likely occur in
Humboldt Harbor each day during the pollock fishing seasons (HDR 2017).
It is assumed that Steller sea lions may be present every day, and also
that take will include multiple harassments of the same individual(s)
both within and among days. It is also assumed that 12 unique
individual sea lions occur in Humboldt Harbor each day and could
potentially be exposed to Level B harassment over 40 days of
construction. Given that the project area is located within the aquatic
zones (i.e., designated critical habitat) of two designated major
haulouts (Sea Lion Rocks and The Whaleback), sea lions could commonly
enter into the Level B ensonified zone outside of the Humboldt Harbor.
As such, it assumed that an additional 12 animals per day may occur in
the Level B harassment zone outside of Humboldt Harbor. Total exposures
is calculated using the following equation:
24 sea lions per day * 40 days of exposure = 960 potential exposures
No Level A take is proposed for Steller sea lions since the Level A
isopleths are smaller than the 100 meter shutdown zone.
Harbor Seal
Anecdotal observations indicate that harbor seals are uncommon in
Humboldt Harbor proper (HDR 2017). However, they are expected to occur
occasionally in the project area. The Kodiak Ferry Terminal and Dock
Improvements Project on Kodiak Island recorded 13 single sightings of
harbor seals during 110 days of monitoring. Although the harbor seal
stock is different at Kodiak (South Kodiak stock) and the project sites
are somewhat dissimilar, NMFS used this information to conservatively
estimate that one harbor seal could be present near Sand Point on any
given day. An aerial haulout survey in 2011 estimated that 15 harbor
seals occupy the survey unit along the south coast of Popof Island
(London et al., 2015) and anecdotal observations indicate that harbor
seals are known to occur intermittently near the airport (HDR 2017).
NMFS conservatively estimates that one animal per day will be observed
near the harbor while another animal will occur near the airport or
elsewhere within an ensonified zone. Therefore, NMFS proposes that up
to two harbor seals may be taken each day during the 40-day pile
installation period for a total of 80 authorized takes.
During impact installation of 30-inch piles, the Level A harassment
isopleth for harbor seals extends out to a maximum distance of 763
meters on days when four piles are driven; out to 339 meters when two
24-inch dolphins are installed on the same day; and out to 241 meters
when four fenders are installed on a single day. Harbor seals often act
curious toward on-shore activities and are known to approach humans,
lifting their heads from the water to look around. Given that harbor
seals are likely to be found in the near-shore environment, we are
proposing limited Level A take since the impact pile driving injury
zones can extend well beyond the 100 meter shutdown zone. We anticipate
that up to one-third of harbor seal takes would be by Level A
harassment resulting in 27 Level A and 53 Level B proposed takes of
harbor seals.
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 such
activity, ``and other means of effecting the least practicable impact
on such species or stock and its habitat, paying particular attention
to rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking'' for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting such activity or other means of effecting the
least practicable adverse impact upon the affected species or stocks
and their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully balance 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 which considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range), as well as
the likelihood that the measure will be effective if implemented; and
the likelihood of effective implementation, and; (2) the practicability
of the measures for applicant implementation, which may consider such
things as cost, impact on operations, and, in the case of a military
readiness activity, personnel safety, practicality of implementation,
and impact on the effectiveness of the military readiness activity.
In addition to the measures described later in this section,
ADOT&PF will employ the following standard mitigation measures:
(a) Conduct briefings between construction supervisors and crews,
and
[[Page 31422]]
marine mammal monitoring team, prior to the start of all pile driving
activity, and when new personnel join the work, in order to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures, and;
(b) For in-water heavy machinery work other than pile driving
(e.g., standard barges, tug boats), if a marine mammal comes within 10
m, operations shall cease and vessels shall reduce speed to the minimum
level required to maintain steerage and safe working conditions. This
type of work could include the following activities: (1) Movement of
the barge to the pile location; or (2) positioning of the pile on the
substrate via a crane (i.e., stabbing the pile).
(c) Work may only occur during daylight hours, when visual
monitoring of marine mammals can be conducted.
The following measures would apply to ADOT&PFs mitigation
requirements:
Establishment of Shutdown Zone--For all pile driving activities,
ADOT&PF will establish a shutdown zone. The purpose of a shutdown zone
is generally to define an area within which shutdown of activity would
occur upon sighting of a marine mammal (or in anticipation of an animal
entering the defined area). In this case, shutdown zones are intended
to contain areas in which SPLs equal or exceed acoustic injury criteria
for some authorized species, based on NMFS' new acoustic technical
guidance published in the Federal Register on August 4, 2016 (81 FR
51693). The shutdown zones vary for specific species. A conservative
shutdown zone of 100 meters will be monitored during all pile driving
activities to prevent Level A exposure to most species. During
vibratory installation of piles of all sizes and impact installation of
24-inch piles, piles under 24 inches, and H-piles, a 100-meter shutdown
zone would prevent Level A take to marine mammals. A 100-meter shutdown
zone would also be sufficient to prevent Level A take of mid-frequency
cetaceans and otariid pinnipeds (i.e., Steller sea lions) during impact
installation of 30-inch and 24-inch piles. Note that Level A take is
not proposed for the low-frequency species of fin whale, gray whale and
minke whale, mid-frequency killer whale and high-frequency Dall's
porpoise since estimated take numbers are low. In the unlikely
occurrence that animals of these species are observed approaching their
respective Level A zones, pile driving operations will shut down.
Establishment of Level A Take Zone--ADOT&PF will establish Level A
take zones which are areas beyond the shutdown zones where animals may
be exposed to sound levels that could result in PTS. During impact
installation of 30-inch and 24-inch piles, a 100-meter shutdown zone
would not be sufficient to prevent Level A take of low-frequency
cetaceans (i.e., humpback whales), high-frequency cetaceans (i.e.,
harbor porpoises), or phocid pinnipeds (i.e., harbor seals). For this
reason, Level A take for small numbers of humpback whales, harbor
porpoises, and harbor seals is proposed.
To account for potential variations in daily productivity during
impact installation, isopleths were calculated for different numbers of
piles that could be installed each day. Therefore, should the
contractor expect to install fewer piles in a day than the maximum
anticipated, a smaller Level A shutdown zone reflecting the number of
piles driven would be required to avoid take. Furthermore, if the first
pile is driven and no marine mammals have been observed within the
radius of corresponding Level A zone, then the Level A radius for the
next pile shall be decreased to next largest Level A radius. This
pattern shall continue unless an animal is observed within the most
recent shutdown zone radius, at which that specific shutdown radius
shall remain in effect for the rest of the workday. Additionally, if
piles of different sizes are installed in a single day, the size of the
monitored Level A zone for all installed piles will default to the
isopleth corresponding to the largest pile being driven that day. Level
A zones will be rounded up to the nearest 10 m and are depicted in
Table 9.
Table 9--Level A Zone Isopleths During Impact Driving
----------------------------------------------------------------------------------------------------------------
Isopleths (m)
Piles installed --------------------------------------------------------
Activity per day LF (Humpback HF (Harbor
whales) porpoises) PW (Harbor seals)
----------------------------------------------------------------------------------------------------------------
Impact Installation 30''............ 4 1,430 (1,426) 1,700 (1,699) 770 (763)
3 1,180 (1,177) 1,410 (1,402) 630 (630)
2 900 (898) 1,070 (1,070) 490 (481)
1 570 (566) 680 (674) 310 (303)
Impact Installation 24'' Dolphin.... 2 640 (633) 760 (754) 340 (339)
1 400 (399) 480 (475) 220 (213)
Impact Installation 24'' Fender..... 4 450 (450) 540 (537) 250 (241)
3 380 (372) 450 (443) 200 (199)
2 290 (284) 340 (338) 160 (152)
1 180 (178) 220 (213) 100 (96)
----------------------------------------------------------------------------------------------------------------
Establishment of Disturbance Zones--ADOT&PF will establish Level B
disturbance zones or zones of influence (ZOI) which are areas where
SPLs equal or exceed 160 dB rms for impact driving and 120 dB rms
during vibratory driving. Disturbance zones provide utility for
monitoring by establishing monitoring protocols for areas adjacent to
the shutdown zones. Monitoring of disturbance zones enables observers
to be aware of and communicate the presence of marine mammals in the
project area but outside the shutdown zone and thus prepare for
potential shutdowns of activity. The Level B zone isopleths will be
rounded up to the nearest 10 m and are depicted in Table 10.
[[Page 31423]]
Table 10--Level B Zone Isopleths During Impact and Vibratory Driving
------------------------------------------------------------------------
Level B
harassment zone
(meters) (based
on practical
spreading loss
Activity model)
------------------
Cetaceans and
Pinnipeds (120
dB)
------------------------------------------------------------------------
Vibratory Installation 30''.......................... 10,970 (10,964)
Vibratory Installation 24'' Dolphin.................. 5,420 (5,412)
Vibratory Installation 24'' Fender................... 5,420 (5,412)
Vibratory Installation and/or removal <24'' or H- 5,420 (5,412)
piles...............................................
------------------------------------------------------------------------
Activity Cetaceans and
Pinnipeds
(160 dB)
------------------------------------------------------------------------
Impact Installation 30''............................. 1,740 (1,738)
Impact Installation 24'' Dolphin..................... 1,740 (1,738)
Impact Installation 24'' Fender...................... 1,740 (1,738)
------------------------------------------------------------------------
Soft Start--The use of a soft-start procedure is believed to
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
will be required to provide an initial set of strikes from the hammer
at 40 percent energy, each strike followed by no less than a 30-second
waiting period. This procedure will be conducted a total of three times
before impact pile driving begins. Soft Start is not required during
vibratory pile driving and removal activities.
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, the observer will observe the shutdown and
monitoring zones for a period of 30 minutes. The shutdown zone will be
cleared when a marine mammal has not been observed within zone for that
30-minute period. If a marine mammal is observed within the shutdown
zone, a soft-start cannot proceed until the animal has left the zone or
has not been observed for 30 minutes (for cetaceans) and 15 minutes
(for pinnipeds). If the Level B harassment zone has been observed for
30 minutes and non-permitted species are not present within the zone,
soft start procedures can commence and work can continue even if
visibility becomes impaired within the Level B zone. If the Level B
zone is not visible while work continues, exposures will be recorded at
the estimated exposure rate for each permitted species. If work ceases
for more than 30 minutes, the pre-activity monitoring of both zones
must recommence.
Sound Attenuation Devices--During impact pile driving, contractors
will be required to use pile caps. Pile caps reduce the sound generated
by the pile, although the level of reduction can vary.
Based on our evaluation of the applicant'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 adverse impact on the affected species
or stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth, ``requirements pertaining to
the monitoring and reporting of such taking.'' The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the
action area (e.g., presence, abundance, distribution, density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
Visual Marine Mammal Observation
Monitoring will be conducted by qualified marine mammal observers
(MMOs), who are trained biologists, with the following minimum
qualifications:
Independent observers (i.e., not construction personnel)
are required;
At least one observer must have prior experience working
as an observer;
Other observers may substitute education (undergraduate
degree in biological science or related field) or training for
experience;
Ability to conduct field observations and collect data
according to assigned protocols.
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
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 and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior;
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; and
NMFS will require submission and approval of observer CVs.
In order to effectively monitor the pile driving monitoring zones,
two MMOs will be positioned at the best practical vantage point(s). The
monitoring position may vary based on pile driving activities and the
locations of the piles
[[Page 31424]]
and driving equipment. The monitoring location(s) will be identified
with the following characteristics: (1) Unobstructed view of pile being
driven; (2) Unobstructed view of all water within the Level A (if
applicable) and Level B harassment zones for pile being driven,
although it is understood that monitoring may be impaired at longer
distances; and (3) Safe distance from pile driving activities in the
construction area. If necessary, observations may occur from two
locations simultaneously. Potential observation locations include the
existing City Dock, the airport, the fish processing facility, or the
quarry hillside located south of the project site.
Observers will be on site and actively observing the shutdown and
disturbance zones during all pile driving and extraction activities.
Observers will use their naked eye with the aid of binoculars, big-eye
binoculars and a spotting scope to search continuously for marine
mammals during all pile driving and extraction activities.
The following additional measures apply to visual monitoring:
If waters exceed a sea-state which restricts the
observers' ability to make observations within 100 m of the pile
driving activity (e.g., excessive wind or fog), pile installation and
removal will cease. Pile driving will not be initiated until the entire
shutdown zone is visible.
If a marine mammal authorized for Level A take is present
within the Level A harassment zone, a Level A take would be recorded.
If Level A take reaches the authorized limit, then pile installation
would be stopped as these species approach the Level A harassment area
to avoid additional take of these species.
If a marine mammal authorized for Level B take is present
in the Level B harassment zone, pile driving activities or soft-start
may begin and a Level B take would be recorded. Pile driving activities
may occur when these species are in the Level B harassment zone,
whether they entered the Level B zone from the Level A zone (if
relevant), shutdown zone or from outside the project area. If Level B
take reaches the authorized limit, then pile installation would be
stopped as these species approach to avoid additional take of these
species.
If a marine mammal is present in the Level B harassment
zone, pile driving activities may be delayed to avoid a Level B take of
an authorized species. Pile driving activities or soft-start would then
begin only after the MMO has determined, through sighting, that the
animal(s) has moved outside the Level B harassment zone or if it has
not been seen in the Level B zone for 30 minutes (for cetaceans) and 15
minutes (for pinnipeds).
If any marine mammal species not authorized for take are
encountered during activities and are likely to be exposed to Level B
harassment, then ADOT&PF must stop pile driving activities and report
observations to NMFS' Office of Protected Resources;
When a marine mammal is observed, its location will be
determined using a rangefinder to verify distance and a GPS or compass
to verify heading.
The MMOs will record any authorized cetacean or pinniped
present in the relevant injury zone. The Level A zones are shown in
Table 9.
The MMOs will record any authorized cetacean or pinniped
present in the relevant disturbance zone. The Level B zones are shown
in Table 10.
Ongoing in-water pile installation may be continued during
periods when conditions such as low light, darkness, high sea state,
fog, ice, rain, glare, or other conditions prevent effective marine
mammal monitoring of the entire Level B harassment zone. MMOs would
continue to monitor the visible portion of the Level B harassment zone
throughout the duration of driving activities.
At the end of the pile driving day, post-construction
monitoring shall be conducted for 30 minutes beyond the cessation of
pile driving;
Data Collection
Observers are required to use approved data forms. Among other
pieces of information, ADOT&PF will record detailed information about
any implementation of shutdowns, including the distance of animals to
the pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, the ADOT&PF will attempt
to distinguish between the number of individual animals taken and the
number of incidents of take. At a minimum, the following information
will be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Detailed information about any implementation of
shutdowns, including the distance of animals to the pile and
description of specific actions that ensued and resulting behavior of
the animal, if any;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
ADOT&PF will notify NMFS prior to the initiation of the pile
driving activities and will provide NMFS with a draft monitoring report
within 90 days of the conclusion of the construction work. This report
will detail the monitoring protocol, summarize the data recorded during
monitoring, and estimate the number of marine mammals that may have
been harassed, including the total number extrapolated from observed
animals across the entirety of relevant monitoring zones. If no
comments are received from NMFS within 30 days of submission of the
draft final report, the draft final report will constitute the final
report. If comments are received, a final report must be submitted
within 30 days after receipt of comments.
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 the authorized number of marine mammals that
might be ``taken'' through harassment, NMFS considers other factors,
such as the likely nature of any responses (e.g., intensity, duration),
the context of any responses (e.g., critical reproductive time or
location, migration, etc.), as well as effects on habitat, the status
of the affected stocks, and the likely effectiveness of the mitigation.
Consistent with the 1989 preamble for NMFS's implementing regulations
(54 FR 40338; September 29, 1989), the
[[Page 31425]]
impacts from other past and ongoing anthropogenic activities are
incorporated into these analyses via their impacts on the environmental
baseline (e.g., as reflected in the regulatory status of the species,
population size and growth rate where known, ongoing sources of human-
caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analyses applies to all
the species listed in Table 3. There is little information about the
nature of severity of the impacts or the size, status, or structure of
any species or stock that would lead to a different analysis for this
activity.
Pile driving and extraction activities associated with the Sand
Point City Dock Replacement Project, as outlined previously, have the
potential to injure, disturb or displace marine mammals. Specifically,
Level A harassment (injury) in the form of PTS may occur to a limited
numbers of three marine mammal species while a total of nine species
could experience Level B harassment (behavioral disturbance). Potential
takes could occur if individuals of these species are present in Level
A or Level B ensonified zones when pile driving or removal is under
way.
No mortality is anticipated to result from this activity. Limited
take of three species of marine mammal by Level A harassment (injury)
is authorized due to potential auditory injury (PTS) that cannot
reasonably be prevented through mitigation. The marine mammals
authorized for Level A take (27 harbor seals, 16 harbor porpoises, and
2 humpback whales) are estimated to experience PTS if they remain
within the outer limits of a Level A harassment zone during the entire
time that impact pile driving would occur during a single day. Marine
mammal species, however, are known to avoid areas where noise levels
are high (Richardson et al.,1995). Animals would likely move away from
the sound source and exit the Level A zone. Because of the proximity to
the source in which the animals would have to approach, and the longer
time in which they would need to remain in a farther proximity from the
sound source within a Level A zone, we believe the likelihood of marine
mammals experiencing PTS is low but acknowledge it could occur.
Although NMFS is authorizing limited take by PTS, the anticipated takes
reflect the onset of PTS, which would be relatively mild, rather than
severe PTS which would be expected to have more impact on an animal's
overall fitness.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff
2006; Lerma 2014). Most likely, individuals will simply move away from
the sound source and be temporarily displaced from the areas of pile
driving, although even this reaction has been observed primarily only
in association with impact pile driving. In response to vibratory
driving, pinnipeds (which may become somewhat habituated to human
activity in industrial or urban waterways) have been observed to orient
towards and sometimes move towards the sound. The pile driving and
extraction activities analyzed here are similar to, or less impactful
than, numerous construction activities conducted in similar locations
in Alaska, which have taken place with no reported serious injuries or
mortality to marine mammals, and no known long-term adverse
consequences from behavioral harassment. Repeated exposures of
individuals to levels of sound that may cause Level B harassment are
unlikely to result in hearing impairment or to significantly disrupt
foraging behavior. Thus, even repeated Level B harassment of some small
subset of the overall stock is unlikely to result in any significant
realized decrease in fitness for the affected individuals, and would
not result in any adverse impact to the stock as a whole.
ADOT&PF's proposed activities are localized and of relatively short
duration. The entire project area is limited to the Sand Point dock
area and its immediate surroundings. Specifically, the use of impact
driving will be limited to approximately 22 hours over the course of up
to 40 days of construction. Total vibratory pile driving time is
estimated at approximately 85 hours over the same period. While impact
driving does have the potential to cause injury to marine mammals,
mitigation in the form of a 100 m shutdown zone should limit exposure
to potentially injurious sound.
The project is not expected to have significant adverse effects on
marine mammal habitat. No important marine mammal reproductive areas,
such as rookeries, are known to exist within the ensonified areas. The
proposed project is located within the aquatic zones (i.e., designated
critical habitat) of two major Steller sea lion haul outs, and the
Level B underwater harassment zone associated with the proposed project
overlaps with a third. The closest major haulout is approximately 27 km
distant. The project activities are limited in time and would not
modify existing marine mammal habitat. EFH near the project area has
been designated for a number of species. While the activities may cause
some fish to leave the area of disturbance, temporarily impacting
marine mammals' foraging opportunities, this would encompass a
relatively small area of habitat leaving large areas of existing fish
and marine mammal foraging habitat unaffected. As such, the impacts to
marine mammal habitat are not expected to cause significant or long-
term negative consequences.
In summary, this negligible impact analysis is founded on the
following factors: (1) The possibility of serious injury or mortality
to authorized species may reasonably be considered discountable; (2)
the likelihood that PTS could occur in a limited number of animals is
low, but acknowledged; (3) the anticipated incidences of Level B
harassment consist of, at worst, temporary modifications in behavior or
potential TTS; (4) the limited temporal and spatial impacts on marine
mammals or their habitat; (5) the absence of any major haul outs or
rookeries near the project area; and (6) the presumed efficacy of the
planned mitigation measures in reducing the effects of the specified
activity to the level of effecting the least practicable impact upon
the affected species. 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 activity will
have only short-term effects on individuals. The specified activity is
not expected to impact rates of recruitment or survival and will
therefore not result in population-level impacts.
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 planned monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from ADOT&PF's Sand Point City Dock Replacement Project
will have a negligible impact on all affected marine mammal species or
stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so,
[[Page 31426]]
in practice, NMFS compares the number of individuals taken to the most
appropriate estimation of the relevant species or stock size in our
determination of whether an authorization is limited to small numbers
of marine mammals.
Table 11 presents the number of animals that could be exposed to
received noise levels that could cause Level A and Level B harassment
for the proposed work at the Sand Point Dock Replacement Project. Our
analysis shows that between <0.01 percent and 3.07 percent of the
populations of affected stocks could be taken by harassment. Therefore,
the numbers of animals authorized to be taken for all species would be
considered small relative to the relevant stocks or populations even if
each estimated taking occurred to a new individual--an extremely
unlikely scenario. For pinnipeds, especially Steller sea lions,
occurring in the vicinity of the project site, there will almost
certainly be some overlap in individuals present day-to-day, and these
takes are likely to occur only within some small portion of the overall
regional stock.
Table 11--Summary of the Estimated Numbers of Marine Mammals Potentially Exposed to Level A and Level B Harassment Noise Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated number Estimated number
of individuals of individuals
potentially potentially
Species (DPS/stock) exposed to the exposed to the DPS/stock abundance (DPS/stock) Percent of population exposed to
Level A Level B Level A or Level B thresholds
harassment harassment
threshold threshold
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion (wDPS)............... 0 960 50,983.............................. 1.88.
Harbor seal (Cook Inlet/Shelikof 27 53 27,386.............................. 0.29.
Strait).
Harbor porpoise (Gulf of Alaska)...... 16 33 31,046.............................. 0.16.
Dall's porpoise (Alaska).............. 0 4 83,400.............................. <0.01.
Killer whale (Gulf of Alaska, Aleutian 0 18 587 (transient)..................... 3.07 (transient).
Islands, and Bering Sea transient or 2,347 (resident).................... 0.76 (resident).
Alaska resident).
Humpback whale \1\ (Central North 2 30 10,103.............................. 0.32.
Pacific).
Fin whale (Northeast Pacific)......... 0 6 1,368 \2\........................... 0.44.
Gray whale (Eastern North Pacific).... 0 2 20,990.............................. <0.01.
Minke whale (Alaska).................. 0 3 2,020 \3\........................... <0.01.
-----------------------------------------------------------------------------------------------------------------
Total............................. 66 590 N/A................................. N/A.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The Hawaii DPS is estimated to account for approximately 89 percent of all humpback whales in the Gulf of Alaska, whereas the Mexico and Western
North Pacific DPSs account for approximately 10.5 percent and 0.5 percent, respectively (Wade et al. 2016; NMFS 2016). Therefore, an estimated 28
animals from Hawaii DPS; 3 from Mexico DPS: And 1 from Western North Pacific DPS.
\2\ Based on 2010 survey of animals north and west of Kenai Peninsula in U.S. waters and is likely an underestimate (Muto et al. 2016b).
\3\ Based on 2010 survey on Eastern Bering Sea shelf. Considered provisional and not representative of abundance of entire stock (Muto et al. 2016a).
N/A: Not Applicable.
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 will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. The proposed
project is not known to occur in a subsistence hunting area. It is a
developed area with regular marine vessel traffic. Additionally,
ADOT&PF has spoken with local officials about concerns regarding
impacts to subsistence uses and none were expressed. Therefore, NMFS
has preliminarily determined that the total taking of affected species
or stocks would not have an unmitigable adverse impact on the
availability of such species or stocks for taking for subsistence
purposes.
Endangered Species Act (ESA)
Issuance of an MMPA authorization requires compliance with the ESA.
There are DPSs of two marine mammal species that are listed as
endangered under the ESA with confirmed or possible occurrence in the
study area: The WNP DPS and Mexico DPS of humpback whale and the
western DPS of Steller sea lion. NMFS will initiate formal consultation
under Section 7 of the ESA with NMFS Alaska Regional Office. NMFS will
issue a Biological Opinion that will analyze the effects to ESA listed
species as well as critical habitat. The ESA consultation will conclude
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 ADOT&PF for conducting pile driving and extraction
activities associated with the reconstruction of the city dock in Sand
Point, Alaska provided the previously mentioned mitigation, monitoring,
and reporting requirements are incorporated. This section contains a
draft of the IHA itself. The wording contained in this section is
proposed for inclusion in the IHA (if issued).
1. This Authorization is valid from August 1, 2018, through July
31, 2019.
2. This Authorization is valid only for activities associated with
in-water construction work at the Sand Point City Dock Replacement
Project in Sand Point, Alaska.
3. General Conditions
(a) A copy of this IHA must be in the possession of ADOT&PF, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species and number of animals authorized for taking by
Level A and Level B harassment are shown in Table 11 and include:
Harbor seal (Phoca vitulina), Steller sea lion (Eumetopias jubatus),
harbor porpoise (Phocoena phocoena), Dall's porpoise
[[Page 31427]]
(Phocoenoides dalli), killer whale (Orcinus orca), gray whale
(Eschrichtius robustus), humpback whale (Megaptera novaeangliae), fin
whale (Balaenoptera physalus) and minke whale (Balaenoptera
acutorostrata).
(c) ADOT&PF shall conduct briefings between construction
supervisors and crews and the marine mammal monitoring team prior to
the start of all pile driving activity.
(d) For in-water heavy machinery work other than pile driving
(e.g., standard barges, tug boats, barge-mounted excavators), if a
marine mammal comes within 10 m, operations shall cease and vessels
shall reduce speed to the minimum level required to maintain steerage
and safe working conditions.
(e) In-water construction work shall occur only during daylight
hours.
4. Prohibitions
(a) The taking, by incidental harassment only, is limited to the
species listed under condition 3(b) above and by the numbers listed in
Table 11 of this notice. The taking by death of these species or the
taking by harassment, injury or death of any other species of marine
mammal is prohibited and may result in the modification, suspension, or
revocation of this Authorization.
5. Mitigation Measures
The holder of this Authorization is required to implement the
following mitigation measures.
(a) Shutdown Measures.
(i) ADOT&PF shall implement shutdown measures if a marine mammal is
detected within or approaching the specified 100 m shutdown zone.
(ii) Shutdown shall occur if low-frequency cetaceans (i.e. fin
whale, gray whale, minke whale), mid-frequency cetaceans (i.e. killer
whale), or high-frequency cetaceans (Dall's porpoise) approach relevant
Level A take isopleths since Level A take of these species is not
authorized.
(ii) ADOT&PF shall implement shutdown measures if the number of any
allotted marine mammal takes reaches the limit under the IHA and if
such marine mammals are sighted within the vicinity of the project area
and are approaching their respective Level A or Level B harassment
zone.
(b) ADOT&PF shall establish Level A harassment zones as shown in
Table 9.
(i) For impact pile driving, the Level A harassment zone defaults
to the isopleth corresponding to the number of piles planned for
installation on a given day as shown in Table 9.
(ii) After the first pile is driven, if no marine mammals have been
observed within the radius of the corresponding Level A zone, then the
Level A radius for the next pile shall be decreased to the next largest
Level A radius. This pattern shall continue unless an animal is
observed within the most recent shutdown zone radius, at which that
specific shutdown radius shall remain in effect for the rest of the
workday.
(ii) If piles of varying sizes are installed in a single day, the
radius of the Level A zone shall default to the isopleth for the
largest pile being driven on that workday.
(b) ADOT&PF shall establish Level B harassment zones for impact and
vibratory driving as shown in Table 10.
(c) Soft Start.
(i) When there has been downtime of 30 minutes or more without
impact pile driving, the contractor shall initiate the driving with
ramp-up procedures described below.
(ii) Soft start for impact hammers requires contractors to provide
an initial set of strikes from the impact hammer at 40 percent energy,
followed by no less than a 30-second waiting period. This procedure
shall be conducted a total of three times before impact pile driving
begins.
(d) Pre-Activity Monitoring.
(i) Prior to the start of daily in-water construction activity, or
whenever a break in pile driving of 30 minutes or longer occurs, the
observer(s) shall observe the shutdown and monitoring zones for a
period of 30 minutes.
(ii) The shutdown zone shall be cleared when a marine mammal has
not been observed within that zone for that 30-minute period.
(iii) If a marine mammal is observed within the shutdown zone, a
soft-start can proceed if the animal is observed leaving the zone or
has not been observed for 30 minutes (for cetaceans) or 15 minutes (for
pinnipeds), even if visibility of Level B zone is impaired.
(iv) If the Level B zone is not visible while work continues,
exposures shall be recorded at the estimated exposure rate for each
permitted species.
(e) Pile caps shall be used during all impact driving.
6. Monitoring
(a) Monitoring shall be conducted by qualified marine mammal
observers (MMOs), with minimum qualifications as described previously
in the Monitoring and Reporting section.
(b) Two observers shall be on site and actively observing the
shutdown and disturbance zones during all pile driving and extraction
activities.
(c) Observers shall use their naked eye with the aid of binoculars,
big-eye binoculars and a spotting scope during all pile driving and
extraction activities.
(d) Monitoring location(s) shall be identified with the following
characteristics:
(i) Unobstructed view of pile being driven;
(ii) Unobstructed view of all water within the Level A (if
applicable) and Level B harassment zones for pile being driven.
(f) If waters exceed a sea-state which restricts the observers'
ability to make observations within the marine mammal shutdown zone of
100 m (e.g., excessive wind or fog), pile installation and removal
shall cease. Pile driving shall not be initiated until the entire
shutdown zone is visible.
(g) If a marine mammal authorized for Level A take is present
within the Level A harassment zone, a Level A take would be recorded.
If Level A take reaches the authorized limit, then pile installation
would be stopped as these species approach the Level A harassment area
to avoid additional take of these species.
(h) If a marine mammal authorized for Level B take is present in
the Level B harassment zone, pile driving activities or soft-start may
begin and a Level B take would be recorded. If Level B take reaches the
authorized limit, then pile installation would be stopped as these
species approach to avoid additional take of these species.
(i) Marine mammal location shall be determined using a rangefinder
and a GPS or compass.
(j) Ongoing in-water pile installation may be continued during
periods when conditions such as low light, darkness, high sea state,
fog, ice, rain, glare, or other conditions prevent effective marine
mammal monitoring of the entire Level B harassment zone. MMOs would
continue to monitor the visible portion of the Level B harassment zone
throughout the duration of driving activities.
(k) Post-construction monitoring shall be conducted for 30 minutes
beyond the cessation of pile driving at end of day.
7. Reporting
The holder of this Authorization is required to:
(a) Submit a draft report on all monitoring conducted under the IHA
within ninety calendar days of the completion of marine mammal and
acoustic monitoring. This report shall detail the monitoring protocol,
summarize the data recorded during monitoring, and estimate the number
of marine mammals that may have been harassed, including the total
number extrapolated from observed animals across the entirety of
relevant monitoring zones. A final report shall be prepared and
submitted within thirty
[[Page 31428]]
days following resolution of comments on the draft report from NMFS.
This report must contain the following:
(i) Date and time that monitored activity begins or ends;
(ii) Construction activities occurring during each observation
period;
(iii) Record of implementation of shutdowns, including the distance
of animals to the pile and description of specific actions that ensued
and resulting behavior of the animal, if any;
(iv) Weather parameters (e.g., percent cover, visibility);
(v) Water conditions (e.g., sea state, tide state);
(vi) Species, numbers, and, if possible, sex and age class of
marine mammals;
(vii) Description of any observable marine mammal behavior
patterns,
(viii) Distance from pile driving activities to marine mammals and
distance from the marine mammals to the observation point;
(ix) Locations of all marine mammal observations; and
(x) Other human activity in the area.
(b) Reporting injured or dead marine mammals:
(i) In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this IHA,
such as an injury (Level A harassment), serious injury, or mortality,
ADOT&PF shall immediately cease the specified activities and report the
incident to the Office of Protected Resources, NMFS, and the Alaska
Regional Stranding Coordinator, NMFS. The report must include the
following information:
1. Time, date, and location (latitude/longitude) of the incident;
2. Name and type of vessel involved;
3. Vessel's speed during and leading up to the incident;
4. Description of the incident;
5. Water depth;
6. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
7. Description of all marine mammal observations and active sound
source use in the 24 hours preceding the incident;
8. Species identification or description of the animal(s) involved;
9. Fate of the animal(s); and
10. Photographs or video footage of the animal(s).
ADOT&PF may not resume their activities until notified by NMFS.
(ii) In the event that ADOT&PF discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), ADOT&PF shall immediately
report the incident to the Office of Protected Resources, NMFS, and the
Alaska Regional Stranding Coordinator, NMFS. The report must include
the same information identified in 6(b)(i) of this IHA. Activities may
continue while NMFS reviews the circumstances of the incident. NMFS
shall work with ADOT&PF to determine whether additional mitigation
measures or modifications to the activities are appropriate.
(iii) In the event that ADOT&PF discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), ADOT&PF shall report the incident
to the Office of Protected Resources, NMFS, and the Alaska Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. ADOT&PF
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
NMFS determines the authorized taking is having more than a negligible
impact on the species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analyses, the draft authorization, and
any other aspect of this Notice of Proposed IHA for ADOT&PF's Sand
Point City Dock Replacement Project. Please include with your comments
any supporting data or literature citations to help inform our final
decision on the request for MMPA authorization.
Dated: June 30, 2017.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2017-14157 Filed 7-5-17; 8:45 am]
BILLING CODE 3510-22-P