Take of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the North Jetty Maintenance and Repairs Project, Coos Bay, Oregon
| Published date | 23 October 2019 |
| Citation | 84 FR 56781 |
| Record Number | 2019-23081 |
| Section | Notices |
| Court | National Oceanic And Atmospheric Administration |
Federal Register, Volume 84 Issue 205 (Wednesday, October 23, 2019)
[Federal Register Volume 84, Number 205 (Wednesday, October 23, 2019)]
[Notices]
[Pages 56781-56803]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-23081]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XR048
Take of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to the North Jetty Maintenance and Repairs
Project, Coos Bay, Oregon
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; two proposed incidental harassment authorizations;
request for comments on proposed authorizations and possible renewals.
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SUMMARY: NMFS has received a request from the U.S. Army Corps of
Engineers (USACE) for two authorizations to take marine mammals
incidental to the pile driving and removal activities over two years
associated with the Coos Bay North Jetty maintenance and repairs
project. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue two incidental harassment
authorizations (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-year renewals that could be issued under certain circumstances and
if all requirements are met, as described in Request for Public
Comments at the end of this notice. NMFS will consider public comments
prior to making any final decision on the issuance of the requested
MMPA authorizations and agency responses will be summarized in the
final notice of our decision.
DATES: Comments and information must be received no later than November
22, 2019.
ADDRESSES: Comments 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 online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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: Stephanie Egger, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review. Under the MMPA, ``take'' is defined as meaning to harass,
hunt, capture, or kill, or attempt to harass, hunt, capture, or kill
any marine mammal.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
These actions are consistent with categories of activities
identified in Categorical Exclusion B4 (incidental harassment
authorizations with no anticipated serious injury or mortality) of the
Companion Manual for NOAA Administrative Order 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of these proposed IHAs qualifies to be categorically
excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA requests.
Summary of Request
On March 18, 2019, NMFS received a request from USACE for two IHAs
to take marine mammals incidental to vibratory pile driving and removal
associated with the North Jetty maintenance and repairs project, Coos
Bay, Oregon over the course of two years with pile installation
occurring during Year 1 and pile removal occurring during Year 2. The
application was deemed adequate and
[[Page 56782]]
complete on September 10, 2019. The USACE's request is for take of a
small number of seven species of marine mammals by Level B harassment
only. Neither USACE nor NMFS expects injury, serious injury or
mortality to result from this activity and, therefore, IHAs are
appropriate. The IHAs, if issued, will be effective from September 1,
2020 through August 31, 2021 for pile driving installation (Year 1) and
from July 1, 2022 through June 30, 2023 for pile removal (Year 2). The
USACE, in coordination with the Oregon Department of Fish and Wildlife
(ODFW) and NMFS' Northwest Region, proposes to conduct pile driving and
removal October 1st through February 15th and June 1st and July 31st to
minimize effects to listed salmonids. Adherence to the in-water work
window is part of USACE's Endangered Species Act (ESA) consultation
under Standard Local Operating Procedures for Endangered Species
(SLOPES) to administer actions authorized or carried out by the USACE
in Oregon (SLOPES IV In-water Over-water Structures). The ODFW will
make the final determination of the in-water work window.
Description of Proposed Activity
Overview
The USACE is proposing to repair critically damaged sections of the
North Jetty, monitor erosion, and to maintain stable deep-draft
navigation through the entrance into Coos Bay. Repair activities
completed now will reduce the risk of jetty failure or a potential
breach of the Coos Bay North Spit (CBNS). The USACE maintains this
jetty system and navigational channels, and is currently proposing
major repair and rehabilitation of the North Jetty. As part of its
mission to build and maintain navigation facilities, the USACE also
continues to maintain ownership of CBNS land to support jetty
monitoring, ensure evaluation access, and to provide construction
staging and stockpile areas in the event jetty maintenance or
navigation repairs are needed. Work associated with the project may
occur year-round beginning in September 2020. The USACE proposes to use
vibratory pile driving/removal for the Material Off-loading Facility
(MOF) portion of the project using 30-inch (in) steel piles and 24-in
AZ sheet piles OR 12-in H piles. The use of AZ-sheets versus H-piles
will be per the contractor's discretion, largely based on site
conditions, material availability, and cost.
Dates and Duration
The USACE currently anticipates that construction for North Jetty
maintenance and repair project will occur over two years. The IHA
application is requesting take that may occur from the pile driving
activities in the first year (September 1, 2020 through August 31,
2021) and from pile removal activities in the second year of pile
driving activities (July 1, 2022 through June 30, 2023). The USACE
proposes to complete pile driving activities between October 1st
through February 15th and June 1st through July 31st each year to
protect salmonids.
The USACE estimates vibratory pile driving may occur over a 1-4
month time period each year but likely would take one month for
installation (Year 1) and one month for removal (Year 2). There would
be an estimate of 7 days of noise expose during pile driving for each
type of pile (i.e., and 30-in steel piles and 24-in AZ sheet piles OR
12-in H piles) for a total of 14 days of pile driving activity each
year. Pile driving may occur up to 6 hours per day depending on the
pile type.
Specific Geographic Region
Coos Bay is an approximately 55.28 km\2\ estuary located in Coos
County on the Oregon coast, approximately 200 miles south of the
Columbia River. The bay provides a harbor- and water-dependent economy
for the local and state community and, as the second largest estuary in
Oregon (14,000 acres), the largest located entirely within state
borders (Hickey and Banas 2003, Arneson 1975), and is an important
biological resource. It is considered the best natural harbor between
San Francisco Bay, California and the Puget Sound, Washington. The
average depth of the Coos estuary is 4 m (13 ft). The Coos estuary
exhibits the typical features of a drowned river valley estuary type.
It features a V-shaped cross section, a relatively shallow and gently
sloping estuary bottom, and a fairly uniform increase in depth from the
upper, river-dominated part of the estuary toward the mouth. Large
expanses of intertidal sand and mud flats complement channels, eelgrass
beds, vegetated marshes, and swamps to provide a diversity of estuarine
habitats.
The entrance to the Coos Bay estuary and navigation channel lies
between Coos Head and the Coos Bay North Spit (CBNS) (see Figure 1-1 of
the application). The Coos Bay north and south jetties stabilize a 1-
mile long, 47[hyphen]foot deep channel. Channel depth decreases to
approximately 37 feet at RM 1 and extends 15 miles upstream where it
runs adjacent to the cities of Charleston, North Bend, and Coos Bay.
The CBNS is a large isolated peninsula about 15 miles from downtown
Coos Bay; supporting unique coastal habitats. The USACE parcel (see
Figure 1-2 of the application) runs north from the boundary of the
North Jetty, to the southern boundary of land owned by the U.S. Bureau
of Land Management (BLM). It is bound by the Pacific Ocean to the west,
which includes South Beach (the beach between the North Jetty and the
FAA towers as shown), and by the Log-Spiral Bay (LSB) and Coos Bay to
the east. The extent of the North Jetty repairs and staging areas of
the overall project area are shown below in Figure 1.
[[Page 56783]]
[GRAPHIC] [TIFF OMITTED] TN23OC19.001
Detailed Description of Specific Activity
The purpose of the proposed action is to repair critically damaged
sections of the North Jetty in order to maintain stable deep-draft
navigation through the entrance into Coos Bay and to prevent breaching
of the CBNS. Completing the proposed repair activities now will reduce
the risk of future jetty failure. Progressive damages to the North
Jetty system over the last 20 years have resulted in an emergency
repair action in 2002 and an interim repair in 2008. The proposed major
maintenance of the Coos Bay North Jetty is critical to keeping the
river and harbor open to deep-draft navigation and to sustaining
important navigation-related components of local and state economies.
The proposed activities would include repair activities for three
main jetty components: The jetty head, root, and trunk. Repair
activities also require re-establishment and repair of the following
three temporary construction features including the MOF, upland staging
areas and road turn-outs to facilitate equipment and material delivery.
Removal and site restoration for each of the temporary construction
features is proposed.
The majority of proposed jetty repairs will be completed within the
existing authorized footprint of the jetty structure, returning
specified sections to pre-erosional conditions. However, the length of
the final repaired jetty (8,425 feet (ft)) will be shorter than its
originally authorized footprint length of 9,600 ft. The jetty head
stabilizes the oceanward end of the jetty structure and is exposed to
the most severe loading. The jetty trunk connects the jetty head to the
jetty root and transitions from a jetty reach exposed to both ocean-
side and channel-side loading, to the root, which is primarily loaded
from the channel-side. Proposed repair elements may include some minor
areas that occur outside of the existing jetty footprint, but are
necessary to maintain jetty function.
[ssquf] Repair of the jetty root entails rebuilding up to 1,600 ft
of the jetty root. Toe protection around the tip of the reconstructed
section would be completed to compensate for accelerated ebb-tidal
flows caused by the reconstructed root. This protection could extend
beyond the area of the existing relic jetty root.
[ssquf] Construction of a rubble-mound jetty head (located
shoreward of the originally authorized North Jetty head). While it is
expected that the vast majority of the head construction will remain on
the relic stone base, there may be some small increase in footprint to
ensure a stable jetty head design.
The USACE proposes to rebuild sections of the jetty root where the
structure has deteriorated at or below the water line. The jetty head
and trunk require extensive repairs, but not to the same extent as the
jetty root, which has not been repaired since the original
construction. Optional repairs to the jetty root could provide
additional stability to LSB and prevent further
[[Page 56784]]
erosion. The optional repairs to the jetty trunk could place larger
stone atop sections that were previously addressed with slightly
smaller stone during an interim repair. Each of these optional repairs
would be contingent on funding availability.
Construction Staging Areas
Jetty repairs and associated construction elements require
additional areas for activities involving equipment and supply staging
and storage, parking areas, access roads, scales, general yard
requirements, and jetty stone stock pile areas. Staging areas are
required to store materials, equipment and tools, field offices, turn
and maneuver trucks, and to provide parking for contractors.
There are three proposed staging areas for the Proposed Action: The
Overland Delivery Staging Area (ODSA, up to about 10 acres), the North
Jetty Staging Area (NJSA, up to 20 combined acres from three alternate
staging areas), and the MOF Staging Area (up to 2.5 acres) (see Figure
1-3 of the application). The MOF Staging Area is where all pile driving
and removal activities will occur. The ODSA was used previously for the
2008 North Jetty Interim Repair Project. The MOF Staging Area, also
previously used and located upland of the MOF itself, would be
necessary to accommodate stockpile and transfer of jetty stone from
barges to transport vehicles prior to delivery to the NJSA. The NJSA
will be a combination of areas; either approximately 20 acres near the
jetty root, on top of the LSB sand placement area, or a jetty root
staging area (1.5 acres) and up to an additional 18.5 acres to be
chosen by the Contractor from the available Alternate Staging Area
locations shown on the plans.
Staging area equipment would include a crane or excavator for
transferring large stones from the highway-transport vehicles to heavy-
duty off-road vehicles, or from a barge to heavy-duty off-road
vehicles, an excavator, front-end loaders, and bulldozers. All of the
stockpile areas would accommodate storage of a range of different sized
jetty stone and other rock and gravel construction materials throughout
the year. Construction of each upland staging area would require
vegetation clearing and site grading, which would be followed by
restoration at the completion of construction.
North Jetty Major Maintenance and Repairs
Most of the proposed jetty stone placement work would use land-
based equipment for construction of the repair and modifications to the
North Jetty. The majority of the work is expected to be conducted from
on top of the jetty using an excavator or a crane. Where appropriate,
there may also be rework and reuse of the existing relic and jetty
prism stone. Most of the proposed stone placement would occur on
existing relic stone that formed the original jetty. The prism
footprint could increase in width compared to the existing prism by
about 10 ft along the length of the proposed repair sections. During
new stone placement, there is a chance of stone slippage down the slope
of the jetty. This is only a remote possibility given the size of the
rocks. Additionally, dropping armor stone from a height greater than 2
ft would be prohibited, further minimizing the risk of stone slippage.
The length of the repaired jetty would remain shorter than its
originally authorized footprint length.
The full width of the repaired jetty crest would double as a
``jetty crest haul road'' that allows construction equipment to access
and reach the entire jetty construction areas (i.e., crest, slope, and
toe). As described in Table 1-2 of the application, up to three
turnouts would also be required every 300 to 500 ft along the length of
the jetty and parallel to the jetty crest haul road for safety purposes
(allows for vehicle and equipment passing and turns while on the
jetty). The footprint of repairs would not extend substantially beyond
the extent of relic jetty stone (possibly up to 10 ft on either side).
Material Offloading Facility (MOF)
The MOF will be constructed from the land waterward using land-
based equipment. The MOF will provide vehicle access to/from the shore.
The MOF could either be a simplified design of singular pipe piles for
mooring a barge with spuds as a dock face, or a more complicated MOF
design with piles supporting mooring dolphins with H or Z-piles to help
retain material. In either case, pilings will be installed by barge
using vibratory pile driving methods. Figure 1-4 of the application
provides a basic overview of potential MOF elements, though the final
configuration of pilings and specifications within the broader scope
will be determined by the contractor. Fill material to construct the
MOF could be obtained from maintenance dredging activities that occur
annually in the Federal Navigation Channel, from dredging at the MOF
site, or from other suitable sources, similar to those that provide the
armor stone and gravel materials for the Project. Any imported material
will be obtained from a clean and permitted source, suitable for in-
water placement. Initial dredging of up to about 24,000 cubic yards may
be required at the MOF to reach draft depth for the delivery barges.
This activity will most likely be completed by mechanical dredge (e.g.,
clamshell). Dredged material from the MOF site will be tested for
contaminants, prior to dredging, following standard USACE and U.S.
Environmental Protection Agency procedures. If clean, material will be
side-cast or used to supplement MOF construction. If not suitable for
ocean placement, dredged material will be transported to a suitable and
certified upland facility. Maintenance dredging at the MOF will occur
throughout construction to maintain depths needed for delivery vessels.
Additional details on the project construction elements can be
found in Section 1 of the project application. The USACE has not
requested, and NMFS does not propose to issue, take from any activities
other than from vibratory pile driving and removal for the MOF.
The type and amount of piles associated with the project are
provided in Table 1.
Table 1--Pile Driving (Year 1) and Removal (Year 2) Associated With the MOF of the North Jetty Repairs and Maintenance Project. The Same Number of Piles
Driven in Year 1 Will Be Removed in Year 2
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Total number Total number Maximum number Maximum number
of piles to be of piles to be of piles of piles
Pile type Size driven (year removed (year driven per day removed per Driving type
1) 2) (year 1) day (year 2)
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Steel Pipe Pile...................... 30-inch................ 24 24 6 6 Vibratory.
Steel H Pile......................... 12-in.................. 40 40 25 25 Vibratory.
Steel AZ Sheet....................... 24-in.................. 100 100 25 25 Vibratory.
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[[Page 56785]]
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting section).
Description of Marine Mammals in the Area of Specified Activities
Systematic marine mammal surveys in Coos Bay are limited;
therefore, the USACE relied on two multi-day AECOM surveys of Coos Bay,
Oregon Department of Fish and Wildlife (ODFW), and anecdotal reports to
better understand marine mammal presence in Coos Bay and in support of
the IHA application. Seven marine mammal species comprising seven
stocks have the potential to occur within Coos Bay during the project.
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 2 lists all species with expected potential for occurrence
around Coos Bay and summarizes information related to the population or
stock, including regulatory status under the MMPA and ESA and potential
biological removal (PBR), where known. For taxonomy, we follow
Committee on Taxonomy (2016). PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS's
SARs). While no mortality is anticipated or authorized here, PBR and
annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species and
other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's U.S. Pacific and Alaska 2018 SARs (e.g., Carretta et al., 2018;
Muto et al., 2018). All values presented in Table 2 are the most recent
available at the time of publication and are available in the 2018 SARs
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports).
Table 2--Marine Mammals Occurrence in the Project Area
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
Blue whale...................... Balaenoptera m. Eastern North Pacific E,D;Y 1,647 (0.07; 1,551; 2.3 >=19
musculus. Stock. 2011).
Humpback whale.................. Megaptera novaeangliae. California/Oregon/ E,D;Y 2,900 (0.05; 2,784; 16.7 >=40.2
Washington Stock. 2014).
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern North Pacific.. N, N 26,960 (0.05, 25,849, 801 139
2016).
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer Whale.................... Orcinus orca........... West Coast Transient... N, N 243 (-, 243, 2006) \4\ 2.4 0
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Northern CA/Southern OR N, N 35,769 (0.52, 23,749, 475 >=0.6
2011).
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Northern elephant sea........... Mirounga angustirostris California breeding.... N, N 179,000 (n/a, 81,368, 4,882 8.8
2010).
Steller sea lion................ Eumetopias jubatus..... Eastern U.S............ N, N 41,638 (-, 41,638, 2,498 108
2015).
California sea lion............. Zalophus californianus. U.S.................... N, N 257,606 (n/a, 233,515, 14,011 >320
2014).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Oregon/Washington Coast N, N 24,732 (0.12, -, 1999) unk unk
\5\.
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
with estimated mortality due to commercial fisheries is presented in some cases.
\4\ The minimum population estimate (NMIN) for the West Coast Transient stock of killer whales is derived from mark-recapture analysis for West Coast
transient population whales from the inside waters of Alaska and British Columbia of 243 whales (95 percent probability interval = 180-339) in 2006
(DFO 2009), which includes animals found in Canadian waters.
\5\ Because the most recent abundance estimate is >8 years old (1999), there is no current estimate of abundance available for this stock. However, for
purposes of this analysis, we apply the previous abundance estimate, corrected for animals missed in the water as described in Carretta et al. (2014)
of 24,732.
[[Page 56786]]
All species that could potentially occur in the proposed survey
areas are included in Table 2. Humpback whales (Megaptera novaeangliae)
and blue whales (Balaenoptera musculus musculus) are not uncommon along
the Oregon coast, however, they are unlikely to enter Coos Bay and be
affected by construction noise. Given these considerations, the
temporary duration of potential pile driving, and noise isopleths that
would not extend beyond the river mouth, there is no reasonable
expectation for proposed activities to affect these species and they
are not discussed further.
As described below, the remaining seven species comprising seven
stocks temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur, and we have proposed
authorizing it.
Gray Whales
Gray whales are only commonly found in the North Pacific. Genetic
comparisons indicate there are distinct ``Eastern North Pacific'' (ENP)
and ``Western North Pacific'' (WNP) population stocks, with
differentiation in both mtDNA haplotype and microsatellite allele
frequencies (LeDuc et al. 2002; Lang et al. 2011a; Weller et al. 2013).
Tagging, photo-identification and genetic studies show that some whales
identified in the WNP off Russia have been observed in the ENP,
including coastal waters of Canada, the U.S. and Mexico (Lang 2010;
Mate et al. 2011; Weller et al. 2012; Urb[aacute]n et al. 2013, Mate et
al. 2015). However, WNP gray whales are not expected to enter Coos Bay
and therefore will not be discussed further.
From 2009 to 2013, researchers attached satellite tags to 35 gray
whales off the coasts of Oregon and northern California from September
to December 2009, 2012, and 2013 (Lagerquist et al., 2019). These
whales are members of the Pacific Coast Feeding Group (PCFG), a subset
of gray whales in the ENP that feed off the PNW, during summer and
fall. Tracking periods for the satellite[hyphen]tagged whales in this
study ranged from 3 days to 383 days. Feeding[hyphen]area home ranges
for the resulting 23 whales covered most of the near[hyphen]shore
waters from northern California to Icy Bay, Alaska, and ranged in size
from 81[thinsp]km\2\ to 13,634[thinsp]km\2\. Core areas varied widely
in size (11-3,976[thinsp]km\2\) and location between individuals, with
the highest[hyphen]use areas off Point St. George in northern
California, the central coast of Oregon, and the southern coast of
Washington. Tag data indicates whales primarily occupied waters
predominantly over continental shelf waters less than 10[thinsp]km from
shore and in depths less than 50[thinsp]m. Gray whales are not known to
enter Coos Bay; however, they do enter larger bays such as San
Francisco Bay during their northward and southward migration and
therefore are included in this analysis.
Since January 1, 2019, elevated gray whale strandings have occurred
along the west coast of North America from Mexico through Alaska. This
event has been declared an Unusual Mortality Event (UME). A UME is
defined under the MMPA as a stranding that is unexpected; involves a
significant die-off of any marine mammal population; and demands
immediate response. As of September 5, 2019, 117 gray whales have
stranded in the U.S. between Alaska and California with an additional
10 strandings in Canada and 81 in Mexico. Of the U.S. strandings, six
of the animals have been found in Oregon. Full or partial necropsy
examinations were conducted on a subset of the whales. Preliminary
findings in several of the whales have shown evidence of emaciation.
These findings are not consistent across all of the whales examined, so
more research is needed. Threats to gray whales include ship strike,
fishery gear entanglement, and climate change-related impacts such as
reduction in prey availability, and increased human activity in the
Arctic (Carretta et. al., 2019).
Killer Whales
Killer whales are found throughout the North Pacific. Along the
west coast of North American, `resident,' transient,' and `offshore'
ecotypes have overlapping distributions and multiple stocks are
recognized within that broader classification scheme. The West Coast
Transient (WCT) Stock includes animals that range from California to
southern Alaska, and is genetically distinct from other transient
populations in the region (i.e., Gulf of Alaska, Aleutian Islands, and
Bering Sea transients and AT1 transients). While not regularly seen in
Coos Bay, anecdotal accounts by ODFW biologists suggest bachelor pods
of transient killer whales may be observed in Coos Bay semi-annually.
In May 2017, a pair of killer whales feeding on what was concluded to
be a seal were opportunistically observed in Coos Bay (AECOM 2017). The
whales moved through the estuary northwards past Jordan Cove to the
Highway 101 Bridge. However, the whales are not known to linger in the
area and no biologically important habitat for this stock exists in
Coos Bay.
Harbor Porpoise
In the Pacific Ocean, harbor porpoise are found in coastal and
inland waters from Point Conception, California to Alaska and across to
Kamchatka and Japan (Gaskin 1984). There are several stocks of harbor
porpoise along the west coast of the U.S. and in inland waterways.
While harbor porpoise are rare within Coos Bay, if present, animals are
likely belonging to the Northern California/Southern Oregon stock which
is delimited from Port Arena, California in the south to Lincoln City,
Oregon. Use of Coos Bay by this stock is rare.
Northern Elephant Seal
Northern elephant seals are found occasionally in Oregon either
resting or molting (shedding their hair) on sandy beaches. Elephant
seals do not generally breed in Oregon; however, there are a number of
breeding sites in California such as Ano Nuevo State Reserve. Cape
Arago State Park, just south of the entrance to Coos Bay, is the only
spot where northern elephant seals haulout year-around in Oregon. The
majority of the elephant seals seen in Oregon are sub-adult animals
that come to shore to molt. Northern elephant seals regularly occur at
haul-out sites on Cape Arago, approximately 3.7 miles south of the
entrance to Coos Bay. Scordino (2006) reported total counts (average,
maximum, minimum) of harbor seal, elephant seal, California sea lion,
and Steller sea lion at Cape Arago during each month surveyed between
2002 and 2005. Abundance of elephant seals was low in all months, with
a maximum of 54 animals reported in May (Scordino 2006). No Northern
elephant seals have been observed within Coos Bay; however, given their
close proximity to the mouth of the estuary, they have been included in
this analysis.
California Sea Lion
California sea lions are distributed along the North Pacific waters
from central Mexico to southeast Alaska, with breeding areas restricted
primarily to island areas off southern California (the Channel
Islands), Baja California, and in the Gulf of California (Wright et
al., 2010). There are five genetically distinct geographic populations.
The population seen in Oregon is the Pacific Temperate stock, which are
commonly seen in Oregon from September through May (ODFW 2015). The
approximate growth rate for this species is 5.4 percent annually
(Caretta et al., 2004).
Almost all California sea lions in the Pacific Northwest are sub-
adult or adult
[[Page 56787]]
males (NOAA 2008). The occurrence of the California sea lion along the
Oregon coast is seasonal with lowest abundance in Oregon in the summer
months, from May to September, as they migrate south to the Channel
Islands in California to breed. During other times of the year, the
primary areas where it comes ashore are Cascade Head, Tillamook County;
Cape Argo, Coos County; and Rouge Reef and Orford Reef in Curry County.
The California sea lion stock has been growing steadily since the
1970s. The stock is estimated to be approximately 40 percent above its
maximum net productivity level (MNPL = 183,481 animals), and it is
therefore considered within the range of its optimum sustainable
population (OSP) size (Laake et al., 2018). The stock is also near its
estimated carrying capacity of 275,298 animals (Laake et al., 2018).
However, there remain many threats to California sea lions including
entanglement, intentional kills, harmful algal blooms, and climate
change. For example, for each 1 degree Celsius increase in sea surface
temperature (SST), the estimated odds of survival declined by 50
perfect for pups and yearlings, while negative SST anomalies resulted
in higher survival estimates (DeLong et al., 2017). Such declines in
survival are related to warm oceanographic conditions (e.g., El
Ni[ntilde]o) that limit prey availability to pregnant and lactating
females (DeLong et al., 2017). Changes in prey abundance and
distribution have been linked to warm-water anomalies in the California
Current that have impacted a wide range of marine taxa (Cavole et al.,
2016).
There were at least eight California sea lions sighted
opportunistically during the 2017 AECOM surveys (ACEOM, 2017). No pups
were observed.
Steller Sea Lion
The Steller sea lion range extends along the Pacific Rim, from
northern Japan to central California. For management purposes, Steller
sea lions inhabiting U.S. waters have been divided into two DPS: The
Western U.S. and the Eastern U.S. The population known to occur within
the Lower Columbia River is the Eastern DPS. The Western U.S. stock of
Steller sea lions are listed as endangered under the ESA and depleted
and strategic under the MMPA. The Eastern U.S. stock (including those
living in Oregon) was de-listed in 2013 following a population growth
from 18,000 in 1979 to 70,000 in 2010 (an estimated annual growth of
4.18 percent) (NOAA 2013). A population growth model indicates the
eastern stock of Steller sea lions increased at a rate of 4.76 percent
per year (95 percent confidence intervals of 4.09-5.45 percent) between
1989 and 2015 based on an analysis of pup counts in California, Oregon,
British Columbia, and Southeast Alaska (Muto et al., 2017). This stock
is likely within its OSP; however, no determination of its status
relative to OSP has been made (Muto et al., 2017).
Steller sea lions can be found along the Oregon coast year-round
with breeding occurring in June and July. The southern coast of Oregon
supports the largest Steller breeding sites in U.S. waters south of
Alaska, producing some 1,500 pups annually. Near the entrance of Coos
Bay, Steller sea lions can be found year round at Cape Arago State
Park. The most recent Steller sea lion survey at Cape Arago was June
29, 2017, during which ODFW counted 910 non-pup Steller sea lions
ashore. Steller sea lions may occasionally enter Coos Bay; however, no
long-term residency patterns have been observed. One Steller sea lion
was sighted opportunistically during the 2017 AECOM surveys (ACEOM
2017). No pups were observed.
Harbor Seal
Harbor seals inhabit coastal and estuarine waters off Baja
California, north along the western coasts of the continental U.S.,
British Columbia, and Southeast Alaska, west through the Gulf of Alaska
and Aleutian Islands, and in the Bering Sea north to Cape Newenham and
the Pribilof Islands (Caretta et al., 2014). Within U.S. west coast
waters, five stocks of harbor seals are recognized: (1) Southern Puget
Sound (south of the Tacoma Narrows Bridge); (2) Washington Northern
Inland Waters (including Puget Sound north of the Tacoma Narrows
Bridge, the San Juan Islands, and the Strait of Juan de Fuca); (3) Hood
Canal; (4) Oregon/Washington Coast; and (5) California. Seals belonging
to the Oregon/Washington Coast stock are included in this analysis.
Harbor seals generally are non-migratory, with local movements
associated with tides, weather, season, food availability, and
reproduction (Scheffer and Slipp 1944; Fisher 1952; Bigg 1969, 1981).
Harbor seals do not make extensive pelagic migrations, though some long
distance movement of tagged animals in Alaska (900 km) and along the
U.S. west coast (up to 550 km) have been recorded (Brown and Mate 1983,
Herder 1986, Womble 2012). Harbor seals have also displayed strong
fidelity to haulout sites (Pitcher and Calkins 1979, Pitcher and
McAllister 1981).
The harbor seal is the most widespread and abundant resident
pinniped in Oregon. They haul out to rest at low tide on sand bars in
most bays and estuaries along the Oregon coast. They are also found on
nearshore rocks and islands usually within 3 miles of the coast. Within
Coos Bay, four harbor seal haulout sites have been identified by ODFW
(Wright 2013); three of which have documented pup sightings. From the
inlet to the upper Bay, these are South Slough (southeast of the
entrance channel), Pigeon Point, Clam Island, and Coos Port. However,
only three of the four haulouts are in the project area including the
South Slough, Pigeon Point, and Clam Island (see Figure 4-1 of the
application). Harbor seals generally foraging with in close proximity
to their haulouts. For example, a study of radio tagged harbor seals in
San Francisco Bay found that the majority of foraging trips were less
than 10 km from their regular haulout (Grigg et al., 2012), and a
similar study in Humboldt Bay found that the majority of seals
travelled 13 km or less to forage (Ougzin 2013). Both studies found
that harbors seals typically forage at in relatively shallow water
depths; a median value of 7 m was reported for the San Francisco Bay
Study (Grigg et al., 2012).
The most recent haulout counts were conducted by ODFW in May and
June 2014. In 2014, 333 seals were observed at Coos Bay haulouts in
June (Wright, pers comm., August 27, 2019). May yielded slightly higher
numbers, as expected since it is closer to peak pupping season;
however, the South Slough haulout site was not surveyed in May due to
fog.
Marine mammal presence and abundance data collection throughout
Coos Bay in 2017 and 2018. These surveys were vessel based line
transect surveys. Observations made by AECOM during May 2017 site-
specific surveys found similar patterns to the ODFW aerial surveys.
More than 350 observations of harbor seals were recorded in the estuary
over the four days of survey. AECOM conducted additional surveys during
November and December 2018 using vessel based line transect surveys and
aerial surveys using a drone to establish a fall/winter local abundance
estimate for harbor seals. A maximum of 167 seals were hauled out
between the Clam Island and Pigeon Point haulouts at any one time. ODFW
indicates it is likely many harbor seals are year-round residents in
Coos Bay and relay on these waters for all life stages and behaviors
including, by not limited to, breeding, pupping, and foraging (Wright
2013).
[[Page 56788]]
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Generalized hearing
Hearing group range*
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales) 7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The phocid pinniped functional hearing group was modified from
Southall et al. (2007) on the basis of data indicating that phocid
species have consistently demonstrated an extended frequency range of
hearing compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Seven marine mammal species (three cetacean and four pinniped (three
otariid and one phocid) species) have the reasonable potential to co-
occur with the proposed survey activities. Please refer to Table 2. Of
the cetacean species that may be present, one is classified as a low-
frequency cetacean (i.e., all mysticete species), one is classified as
a mid-frequency cetacean (i.e., all delphinid and ziphiid species and
the sperm whale), and one is classified as a high-frequency cetacean
(i.e., harbor porpoise and Kogia spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
Description of Sound and the Sources Used
This section contains a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used in this
proposal inasmuch as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document. For general
information on sound and its interaction with the marine environment,
please see, e.g., Au and Hastings (2008); Richardson et al. (1995);
Urick (1983).
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 or corresponding points of a sound wave
(length of one cycle). Higher frequency sounds have shorter wavelengths
than lower frequency sounds, and typically attenuate (decrease) more
rapidly, except in certain cases in shallower water. Amplitude is the
height of the sound pressure wave or the ``loudness'' of a sound and is
typically described using the relative unit of the decibel (dB). A
sound pressure level (SPL) in dB is described as the ratio between a
measured pressure and a reference pressure (for underwater sound, this
is 1 microPascal ([mu]Pa)), and is a logarithmic unit that accounts for
large variations in amplitude; therefore, a relatively small change in
dB corresponds to large changes in sound pressure. The source level
(SL) represents the SPL referenced at a distance of 1 m from the source
(referenced to 1 [mu]Pa), while the received level is the SPL at the
listener's position (referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they
[[Page 56789]]
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.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy in a stated frequency band over a stated
time interval or event, and considers both intensity and duration of
exposure. The per-pulse SEL is calculated over the time window
containing the entire pulse (i.e., 100 percent of the acoustic energy).
SEL is a cumulative metric; it can be accumulated over a single pulse,
or calculated over periods containing multiple pulses. Cumulative SEL
represents the total energy accumulated by a receiver over a defined
time window or during an event. Peak sound pressure (also referred to
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous
sound pressure measurable in the water at a specified distance from the
source, and is represented in the same units as the rms sound pressure.
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 a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for sound produced by the
pile driving activity considered here. 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, which is
defined as environmental background sound levels lacking a single
source or point (Richardson et al., 1995). 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., wind and
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
(e.g., vessels, dredging, construction) sound. A number of sources
contribute to ambient sound, including wind and waves, which are a main
source of naturally occurring ambient sound for frequencies between 200
hertz (Hz) and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient
sound levels tend to increase with increasing wind speed and wave
height. Precipitation can become an important component of total sound
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times. Marine mammals can contribute significantly to ambient sound
levels, as can some fish and snapping shrimp. The frequency band for
biological contributions is from approximately 12 Hz to over 100 kHz.
Sources of ambient sound related to human activity include
transportation (surface vessels), dredging and construction, oil and
gas drilling and production, geophysical surveys, sonar, and
explosions. Vessel noise typically dominates the total ambient sound
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.
The sum of the various natural and anthropogenic sound sources that
comprise ambient sound at any given location and time depends not only
on the source levels (as determined by current weather conditions and
levels of biological and human 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 decibels (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.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). 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.
The distinction between these two sound types is not always obvious, as
certain signals share properties of both pulsed and non-pulsed sounds.
A signal near a source could be categorized as a pulse, but due to
propagation effects as it moves farther from the source, the signal
duration becomes longer (e.g., Greene and Richardson, 1988).
Pulsed sound sources (e.g., airguns, 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, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) 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 intermittent (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. The
duration of such sounds, as received at a distance, can be greatly
extended in a highly reverberant environment.
The impulsive sound generated by impact hammers is characterized by
rapid rise times and high peak levels. Vibratory hammers produce non-
impulsive, continuous noise at levels significantly lower than those
produced by impact hammers. Rise time is slower, reducing the
probability and severity of injury, and sound energy is distributed
over a greater amount of time (e.g., Nedwell and Edwards, 2002; Carlson
et al., 2005).
Acoustic Effects on Marine Mammals
We previously provided general background information on marine
mammal hearing (see Description of Marine Mammals in the Area of the
Specified Activity section). Here, we discuss the potential effects of
sound on marine mammals.
Note that, in the following discussion, we refer in many cases to a
review article concerning studies of noise-induced hearing loss
conducted from 1996-2015 (i.e., Finneran, 2015). For study-specific
citations, please see that work. Anthropogenic sounds cover a broad
range of frequencies and sound levels and can have a range of highly
[[Page 56790]]
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; G[ouml]tz et
al., 2009). 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. We first describe specific
manifestations of acoustic effects before providing discussion specific
to pile driving.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects (i.e., certain non-auditory
physical or physiological effects) only briefly as we do not expect
that there is a reasonable likelihood that pile driving may result in
such effects (see below for further discussion). Potential effects from
impulsive sound sources can range in severity from effects such as
behavioral disturbance or tactile perception to physical discomfort,
slight injury of the internal organs and the auditory system, or
mortality (Yelverton et al., 1973). 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; Tal et al., 2015). The construction activities considered
here do not involve the use of devices such as explosives or mid-
frequency tactical sonar that are associated with these types of
effects.
Threshold Shift--NMFS defines a noise-induced threshold shift (TS)
as ``a change, usually an increase, in the threshold of audibility at a
specified frequency or portion of an individual's hearing range above a
previously established reference level'' (NMFS, 2016). The amount of
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007).
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS
(2016), there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing and vocalization frequency range of the
exposed species relative to the signal's frequency spectrum (i.e., how
animal uses sound within the frequency band of the signal; e.g.,
Kastelein et al., 2014), and the overlap between the animal and the
source (e.g., spatial, temporal, and spectral). When analyzing the
auditory effects of noise exposure, it is often helpful to broadly
categorize sound as either impulsive--noise with high peak sound
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. When considering auditory effects, vibratory pile
driving is considered a non-impulsive source while impact pile driving
is treated as an impulsive source.
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). NMFS defines PTS as a permanent, irreversible increase in
the threshold of audibility at a specified frequency or portion of an
individual's hearing range above a previously established reference
level (NMFS 2018). Available data from humans and other terrestrial
mammals indicate that a 40 dB threshold shift approximates PTS onset
(see NMFS 2018 for review). 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).
NMFS defines TTS as a temporary, reversible increase in the
threshold of audibility at a specified frequency or portion of an
individual's hearing range above a previously established reference
level (NMFS 2018). Based on data from cetacean TTS measurements (see
Finneran 2014 for a review), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et
al., 2000; Finneran et al., 2000; Finneran et al., 2002).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships 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
[[Page 56791]]
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 6 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). Given the higher level of sound or longer exposure duration
necessary to cause PTS as compared with TTS, it is considerably less
likely that PTS could occur.
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. Few data
on sound levels and durations necessary to elicit mild TTS have been
obtained for marine mammals.
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 truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and three species of pinnipeds (northern elephant
seal, harbor seal, and California sea lion) exposed to a limited number
of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran 2015). Additionally, the existing marine mammal TTS data come
from a limited number of individuals of cetaceans and pinnipeds. 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), Finneran (2015), and NMFS (2016).
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 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 Gomez et al., 2016 for a review of studies involving marine
mammal behavioral responses to sound.
The acoustic habitat in Coos Bay is regularly elevated by medium to
large-sized boats. Site-specific ambient noise data were collected
during a baseline survey by AECOM in Coos Bay in May 2017 and November
and December 2018. Underwater sound levels for water transit vessels,
which operate throughout the day in Coos Bay, ranged from 152 dB to 177
dB. The results suggested that the ambient noise level was
approximately 120 dB, with high daily variability due to vessel
traffic. We expect some level of habituation and or sensitization,
described in more detail below, to occur due to the existing acoustic
environment in Coos Bay.
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 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). However,
many delphinids approach low-frequency airgun source vessels with no
apparent discomfort or obvious behavioral change (e.g., Barkaszi et
al., 2012), indicating the importance of frequency output in relation
to the species' hearing sensitivity.
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior,
[[Page 56792]]
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, 2013b). 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, 2005, 2006; Gailey et
al., 2007; Gailey et al., 2016).
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., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from airgun surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous
[[Page 56793]]
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).
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; Erbe et al.,
2016). 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) 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., 2007; 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.
Potential Effects of USACE's Activity--As described previously (see
Description of Active Acoustic Sound Sources section), USACE proposes
to conduct vibratory pile driving in Coos Bay. The effects of pile
driving on marine mammals are dependent on several factors, including
the size, type, and depth of the animal; the depth, intensity, and
duration of the pile driving sound; the depth of the water column; the
substrate of the habitat; the standoff distance between the pile and
the animal; and the sound propagation properties of the environment. It
is likely that the onset of pile driving could result in temporary,
short term changes in an animal's typical behavioral patterns and/or
avoidance of the affected area. These behavioral changes may include
(Richardson et al., 1995): Changing durations of surfacing and dives,
number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); avoidance of areas where sound sources are located; and/or
flight responses.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al., 2007).
Sounds produced by vibratory driving or removal would be active for
relatively short durations, with relation to potential for masking. The
frequencies output by pile driving activity are lower than those used
by most species expected to be regularly present for communication or
foraging. We would expect any masking to occur concurrently within the
zones of
[[Page 56794]]
behavioral harassment already estimated for vibratory pile driving and
removal, and which have already been taken into account in the exposure
analysis.
The biological significance of behavioral disturbance is difficult
to predict, especially if the detected disturbances appear minor.
While, generally speaking, the consequences of behavioral modification
could be expected to be biologically significant if the change affects
growth, survival, or reproduction, significant behavioral modifications
that could lead to impacts on health or fitness, such as drastic
changes in diving/surfacing patterns or significant habitat abandonment
are extremely unlikely to result from this activity.
Anticipated Effects on Marine Mammal Habitat
The proposed activities would not result in permanent impacts to
habitats used directly by marine mammals, but may have potential short-
term impacts to food sources such as forage fish. The proposed
activities could also affect acoustic habitat (see masking discussion
above), but meaningful impacts are unlikely. There are no known
foraging hotspots, or other ocean bottom structures of significant
biological importance to marine mammals present in the marine waters in
the vicinity of the project areas. Therefore, the main impact issue
associated with the proposed activity would be temporarily elevated
sound levels and the associated direct effects on marine mammals, as
discussed previously in this preamble. The most likely impact to marine
mammal habitat occurs from pile driving effects on likely marine mammal
prey (i.e., fish) near the MOF. Impacts to the immediate substrate
during installation and removal of piles are anticipated, but these
would be limited to minor, temporary suspension of sediments, which
could impact water quality and visibility for a short amount of time,
but which would not be expected to have any effects on individual
marine mammals. Impacts to substrate are therefore not discussed
further.
Effects to Prey--Sound may affect marine mammals through impacts on
the abundance, behavior, or distribution of prey species (e.g.,
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies
by species, season, and location and, for some, is not well documented.
Here, we describe studies regarding the effects of noise on known
marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, although several are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fish from pile driving activities at the
project areas would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the expected
short daily duration of individual pile driving events and the
relatively small areas being affected.
Any behavioral avoidance by fish of the disturbed area would still
leave significantly large areas of fish and marine mammal foraging
habitat in the nearby vicinity. As described in the preceding, the
potential for pile driving or removal to affect the availability of
prey to marine mammals or to meaningfully impact the quality of
physical or acoustic habitat is considered to be insignificant. Effects
to habitat will not be discussed further in this document.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through these IHAs, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Take of marine mammals incidental to USACE's pile driving and
removal activities could occur by Level B harassment only, as pile
driving has the potential to result in disruption of behavioral
patterns for individual marine mammals. Based on the nature of the
activity, Level A harassment is neither anticipated nor proposed to be
authorized. The proposed mitigation
[[Page 56795]]
and monitoring measures are expected to minimize the severity of such
taking to the extent practicable. As described previously, no mortality
is anticipated or proposed to be authorized for this activity. Below we
describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the proposed take
estimates for each IHA.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source (e.g., frequency, predictability, duty cycle), the environment
(e.g., bathymetry), and the receiving animals (hearing, motivation,
experience, demography, behavioral context) and can be difficult to
predict (Southall et al., 2007, Ellison et al., 2012). Based on what
the available science indicates and the practical need to use a
threshold based on a factor that is both predictable and measurable for
most activities, NMFS uses a generalized acoustic threshold based on
received level to estimate the onset of behavioral harassment. NMFS
predicts that marine mammals are likely to be behaviorally harassed in
a manner we consider Level B harassment when exposed to underwater
anthropogenic noise above received levels of 120 dB re 1 [mu]Pa (rms)
for continuous (e.g., vibratory pile-driving, drilling) and above 160
dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., impact pile
driving seismic airguns) or intermittent (e.g., scientific sonar)
sources. The USACE's proposed activities include the use of continuous,
non-impulsive (vibratory pile driving) therefore, the 120 dB re 1
[mu]Pa (rms) is applicable.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise. The
technical guidance identifies the received levels, or thresholds, above
which individual marine mammals are predicted to experience changes in
their hearing sensitivity for all underwater anthropogenic sound
sources, and reflects the best available science on the potential for
noise to affect auditory sensitivity by:
[ssquf] Dividing sound sources into two groups (i.e., impulsive and
non- impulsive) based on their potential to affect hearing sensitivity;
[ssquf] Choosing metrics that best address the impacts of noise on
hearing sensitivity, i.e., sound pressure level (peak SPL) and sound
exposure level (SEL) (also accounts for duration of exposure); and
[ssquf] Dividing marine mammals into hearing groups and developing
auditory weighting functions based on the science supporting that not
all marine mammals hear and use sound in the same manner.
These thresholds were developed by compiling and synthesizing the
best available science, and are provided in Table 4 below. The
references, analysis, and methodology used in the development of the
thresholds are described in NMFS 2018 Technical Guidance, which may be
accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technicalguidance.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds\*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[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.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
Sound Propagation
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a
[[Page 56796]]
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 * log10(R1/R2),
Where
B = transmission loss coefficient (assumed to be 15)
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log(range)). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log(range)). As is
common practice in coastal waters, here we assume practical spreading
loss (4.5 dB reduction in sound level for each doubling of distance).
Practical spreading is a compromise that is often used under conditions
where water depth increases as the receiver moves away from the
shoreline, resulting in an expected propagation environment that would
lie between spherical and cylindrical spreading loss conditions.
Sound Source Levels
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. There are source level
measurements available for certain pile types and sizes from the
similar environments recorded from underwater pile driving projects
(CALTRANS 2015, WSDOT 2010) that were used to determine reasonable
sound source levels likely result from the USACE's pile driving and
removal activities (Table 5).
Table 5--Predicted Sound Source Levels for Both Installation and Removal
of Piles
------------------------------------------------------------------------
Sound
source
Pile type level at
10 meters
------------------------------------------------------------------------
12-inch steel H-pile 1..................................... 150 dBRMS
24-inch AZ steel sheet 1................................... 160 dBRMS
30-inch steel pipe pile 2.................................. 164 dBRMS
------------------------------------------------------------------------
\1\ Average typical sound pressure levels referenced from Caltrans
(2015) and were either measured or standardized to 10 m from the pile.
\2\ Average sound pressure levels measured at the Vashon Ferry Terminal
(WSDOT, 2010).
Level A Harassment
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources (such as from
vibratory pile driving), NMFS User Spreadsheet predicts the closest
distance at which, if a marine mammal remained at that distance the
whole duration of the activity, it would incur PTS. Inputs used in the
User Spreadsheet (Table 6), and the resulting isopleths are reported
below (Table 7).
Table 6--NMFS Technical Guidance (2018) User Spreadsheet Input To Calculate PTS Isopleths for Vibratory Pile
Driving
[User spreadsheet input--Vibratory Pile Driving Spreadsheet Tab A.1 Vibratory Pile Driving Used]
----------------------------------------------------------------------------------------------------------------
12-in H piles 24-in sheet piles 30-in piles
(install/removal) (install/removal) (install/remove)
----------------------------------------------------------------------------------------------------------------
Source Level (RMS SPL)........................ 150 160 164
Weighting Factor Adjustment (kHz)............. 2.5 2.5 2.5
Number of piles within 24-hr period........... 25 25 6
Duration to drive a single pile (min)......... 10 10 60
Propagation (xLogR)........................... 15 15 15
Distance of source level measurement (meters). 10 10 10
----------------------------------------------------------------------------------------------------------------
Table 7--NMFS Technical Guidance (2018) User Spreadsheet Outputs to Calculate Level A Harassment PTS Isopleths.
--------------------------------------------------------------------------------------------------------------------------------------------------------
User spreadsheet output PTS isopleths (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Levl A harassment
-------------------------------------------------------------------------------
Activity Sound source level at 10 m High-
Low- frequency Mid- frequency frequency Phocid Otariid
cetaceans cetaceans cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
12-in H pile steel installation/removal... 150 dB SPL.................. 3.3 0.3 4.8 2.0 0.1
[[Page 56797]]
24-in sheet pile installation/removal..... 160 dB SPL.................. 15.2 1.3 22.4 9.2 0.6
30-in pile installation/removal........... 164 dB SPL.................. 35.7 3.2 52.8 21.7 1.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Harassment
Utilizing the practical spreading loss model, USACE determined
underwater noise will fall below the behavioral effects threshold of
120 dB rms for marine mammals at the distances shown in Table 8 for
vibratory pile driving/removal. Table 8 below provides all Level B
harassment radial distances (m) and their corresponding areas (km\2\)
during the USACE's proposed activities. It is undetermined whether
sheet piles, H-piles, or a combination of the two will be used for MOF
construction; therefore, the USACE estimated potential take based on
the larger disturbance zone for Level B harassment (i.e., for sheet
pile--9.1 km\2\) for the 12-inch H pile Level B harassment zone.
Table 8--Radial Distances (meters) to Relevant Behavioral Isopleths and Associated Ensonified Areas (square
kilometers (km2)) Using the Practical Spreading Model
----------------------------------------------------------------------------------------------------------------
Level B
Activity Received level at 10 m harassment Level B harassment zone
zone (m)* (km2)
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
12-inch H piles installation/removal.... 150 dB SPL................ 1,000 9.1 (actual calculated
zone is 2).
24-inch sheet pile installation/removal. 160 dB SPL................ 4,642 9.1
30-inch pile installation/removal....... 164 dB SPL................ 8,577 11.5
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations. Potential exposures to vibratory pile driving/removal for
each acoustic threshold were estimated using group size estimates and
local observational data to create a density estimate. As previously
stated, take by Level B harassment only will be considered for this
action. Distances to Level A harassment thresholds are relatively small
and mitigation is expected to avoid Level A harassment from these
activities.
Harbor Seals
Over the last several decades, intermittent and independent surveys
of harbor seal haul outs in Coos Bay have been conducted. The most
recent aerial survey of haulouts occurred in 2014 by ODFW. Those
surveys were conducted during a time when the highest number of animals
would be expected to haul out (i.e., the latter portion of the pupping
season (May and June) and at low tide). In 2014, 333 seals were
observed at Coos Bay haulouts in June (Wright, pers comm., August 27,
2019).
AECOM conducted surveys vessel-based surveys in May/June 2017 and
November 2018 from the Highway 101 Bridge to the seaward entrance to
the Coos Bay estuary. In 2017, during the line transect surveys, there
were an estimated 374 harbor seals counted in 19 groups with a relative
density of 6.2 harbor seals/km. In 2018, because of the low number of
harbor seals sightings during the line transect effort, reliable
statistical estimates of species density could not be accurately
calculated. However, for comparison with the May 2017 data, the number
of seals observed/km yielded a sighting rate of 0.12 harbor seals/km.
AECOM also conducted three days of aerial (drone) flyovers at the
Clam Island and Pigeon Point haulouts to capture aerial imagery during
November and December 2018 to determine a fall/winter estimate for
harbor seals. This aerial field effort observed a maximum of 167 harbor
seals hauled out at Clam Island and 41 harbor seals hauled out at
Pigeon Point on any one day. Based on these counts, an estimate of
relative density was determined for the study area and ranged from 8.5-
11.1 harbor seals/km\2\. Because the pile driving and removal for the
MOF will likely occur over the winter season and to be conservative,
USACE used the maximum density of 11.1 harbor seals/km\2\ to calculate
take.
The estimated take for each IHA was calculated using this density
multiplied by the area ensonified above the threshold (9.1 km\2\ for
sheet piles and 11.5 km\2\ for 30-in piles) multiplied by the number of
days per activity (e.g., 7 days of vibratory pile driving per pile type
for a total of 14 days of pile driving activity each year). Therefore,
a total of 1,601 instances of take by Level B harassment are proposed
for harbor seals in both Year 1 for installation and in Year 2 for
removal (Table 9). Because the Level A harassment zones are relatively
small (21.7 m at the largest for pile driving/removal of 30-in piles),
and activities will occur over a small number of days, we believe the
Protected Species Observer (PSO) will be able to effectively monitor
the Level A harassment zones and we do not anticipate take by Level A
harassment of harbor seals.
[[Page 56798]]
California Sea Lions and Steller Sea Lions
No data are available to calculate density estimates California sea
lion and Steller sea lions; therefore, USACE considers likely
occurrences in estimating take for California sea lions and Steller sea
lions. As described in the Description of Marine Mammals section, no
haulouts for California sea lions and Steller sea lions exist within
Coos Bay where harassment from exposure to pile driving could occur,
however, these species do haul out on the beaches adjacent to the
entrance to Coos Bay. These animals forage individually and seasonal
use of Coos Bay have been observed, primarily in the spring and summer
when prey are present. The estimate for daily California sea lion and
Steller sea lions abundance (n = 1) was based on recent marine mammal
surveys in Coos Bay (AECOM 2017).
For this reason, USACE estimates one California and Steller sea
lion may be present each day of pile driving. We multiplied 1 animal by
the number of days per activity (e.g., 7 days of vibratory pile driving
per pile type). Therefore, a total of 14 instances of take by Level B
harassment are proposed for both California sea lions and Steller sea
lions in both Year 1 for installation and in Year 2 for removal (Table
9). Because the Level A harassment zones are relatively small (Less
than 2 m at the largest for pile driving/removal of 30-in piles), and
activities will occur over a small number of days, we believe the PSO
will be able to effectively monitor the Level A harassment zones and we
do not anticipate take by Level A harassment of California sea lions or
Steller sea lions.
Northern Elephant Seals
The abundance estimate for Northern elephant seals was based on the
maximum number of seals observed at Cape Arago, a prominent haulout
site roughly 6 km south of Coos Bay jetties. Surveys were conducted
between 2002 and 2005 (Scordino 2006) and the reference abundance (n =
54) was the maximum count observed. USACE applied a 3.8 percent annual
population growth rate (NMFS 2014c) to approximate the relative
abundance of elephant seals in 2019 (i.e., n = 91). Lastly, an
estimated density of elephant seals was calculated across the project
area extended to include Cape Arago (i.e., approximately 30 km\2\) as a
basis for determining the number of animals that could be present in
Level B harassment zones during vibratory pile driving activities. This
calculated density is 3.03 Northern elephant seals/km\2\. The estimated
take was calculated using this density (3.03 animals/km\2\) multiplied
by the area ensonified above the threshold (9.1 km\2\ for sheet piles
and 11.5 km\2\ for 30-in piles) multiplied by the number of days per
activity (e.g., 7 days of vibratory pile driving per pile type).
Therefore, a total of 437 instances of take by Level B harassment are
proposed for Northern elephant seals in both Year 1 for installation
and in Year 2 for removal (Table 9). Because the Level A harassment
zones are relatively small (21.7-m isopleth at the largest for pile
driving/removal of 30-in piles), and activities will occur over a small
number of days, we believe the PSO will be able to effectively monitor
the Level A harassment zones and we do not anticipate take by Level A
harassment of Northern elephant seals.
Killer Whales
It is not possible to calculate density for killer whales in Coos
Bay as they are not present in great abundance; therefore, USACE
estimates take based on likely occurrence and considers group size.
During migration, the species typically travels singly or as a mother
and calf pair. This species has been reported in Coos Bay only a few
times in the last decade. The typical group size for transient killer
whales is two to four, consisting of a mother and her offspring (Orca
Network 2018). Males and young females also may form small groups of
around three for hunting purposes (Orca Network 2018). Previous
sightings in Coos Bay documented a group of five transient killer
whales in May 2007 (as reported by the Seattle Times) and a pair of
killer whales were observed during the 2017 May surveys. USACE assumes
that a group of two killer whales come into Coos Bay and could enter a
Level B harassment zone for one day in each year of pile driving
activities. Therefore, a total of two instances of take by Level B
harassment are proposed for killer whales in both Year 1 for
installation and in Year 2 for removal (Table 9). Because the Level A
harassment zones are relatively small (Less than a 4-m isopleth at the
largest for pile driving/removal of 30-in piles), and activities will
occur over a small number of days, we believe the PSO will be able to
effectively monitor the Level A harassment zones and we do not
anticipate take by Level A harassment of killer whales.
Harbor Porpoise
It is not possible to calculate density for harbor porpoise in Coos
Bay as they are not present in great abundance; therefore, USACE
estimates take based on likely occurrence and considers group size.
Harbor porpoise are most often seen singly, in pairs, or in groups of
up to 10, although there are reports of aggregations of up to 200
harbor porpoises. No harbor porpoises were detected during recent
marine mammal surveys within the Coos Bay estuary (AECOM 2017, 2018).
However, harbor porpoises were counted during aerial surveys of marine
mammals off the coasts of California, Oregon, and Washington. The
maximum estimated count of harbor porpoises within approximately 1,700
km\2\ of Coos Bay (n = 24 in January 2011) was the basis for estimated
abundance (Adams et al., 2014). USACE applied a 4 percent annual
population growth rate (NMFS 2013a) to approximate the relative
abundance of harbor porpoises in 2019 (i.e., n = 33). Lastly, an
estimated density of harbor porpoise was calculated across
approximately 1,700 km\2\ as a basis for determining the number of
animals that could be present in Level B harassment zones during
vibratory pile driving activities. This calculated density is 0.019
harbor porpoise/km\2\. The estimated take was calculated using this
density (0.019 animals/km\2\) multiplied by the area ensonified above
the threshold (9.1 km\2\ for sheet piles and 11.5 km\2\ for 30-in
piles) multiplied by the number of days per activity (e.g., 7 days of
vibratory pile driving per pile type, 14 total days). Therefore, a
total of four instances of take by Level B harassment are proposed for
harbor porpoise in both Year 1 for installation and in Year 2 for
removal (Table 9). Because the Level A harassment zones are relatively
small (a 52.8-m isopleth at the largest for pile driving/removal of 30-
in piles), and activities will occur over a small number of days, we
believe the PSO will be able to effectively monitor the Level A
harassment zones and we do not anticipate take by Level A harassment of
harbor porpoise.
Gray Whales
It is not possible to calculate density for gray whales in Coos Bay
as they are not present in great abundance; therefore, USACE estimates
take based on likely occurrence and considers group size. Gray whales
are frequently observed traveling alone or in small, unstable groups,
although large aggregations may be seen in feeding and breeding
grounds. The maximum estimated count of gray whales within
approximately 1,700 km\2\ of Coos Bay (n = 10) was the basis for
estimated abundance (Adams et al., 2014). USACE then applied a 6
percent population growth rate (NOAA 2014b) to derive the
[[Page 56799]]
current estimated abundance to approximate the relative abundance of
gray whales in 2019 (i.e., n = 16). Lastly, an estimated density of
gray whales was calculated across approximately 1,700 km\2\ as a basis
for determining the number of animals that could be present in Level B
harassment zones during vibratory pile driving activities. This
calculated density is 0.0094 gray whales/km\2\. The estimated take was
calculated using this density (0.0094 animals/km\2\) multiplied by the
area ensonified above the threshold (9.1 km\2\ for sheet piles and 11.5
km\2\ for 30-in piles) multiplied by the number of days per activity
(e.g., 7 days of vibratory pile driving per pile type, 14 total days).
Therefore, a total of two instances of take by Level B harassment are
proposed for gray whales in both Year 1 for installation and in Year 2
for removal (Table 9). Because the Level A harassment zones are
relatively small (a 35.7-m isopleth at the largest for pile driving/
removal of 30-in piles), and activities will occur over a small number
of days, we believe the PSO will be able to effectively monitor the
Level A harassment zones and we do not anticipate take by Level A
harassment of gray whales.
For both year 1 and year 2, Table 9 below summarizes the proposed
estimated take for all the species described above as a percentage of
stock abundance.
Table 9--Proposed Estimated Take by Level B Harassment and as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Level B Level B Level B Total take by Level B Total take by Level B
harassment AZ harassment 30- harassment AZ harassment 30- harassment (percent by harassment (percent
sheets (or H- inch piles sheets (or H- inch piles stock) by stock)
Marine mammal plies) ------------------ plies) ---------------------------------------------------------------
------------------ ----------------
YR-1 YR-1 YR-2 removal YR-2 removal YR-1 installation YR-2 removal
----------------------------------------installation------installation----------------------------------------------------------------------------------
Harbor seal (Phoca vitulinai)....... 707 894 707 894 1,601 (2.3 percent)... 1,601 (2.3 percent).
Northern Elephant seal (Mirounga 193 244 193 244 437 (0.2 percent)..... 437 (0.2 percent).
angustirostris).
Steller sea lion (Eumetopias 7 7 7 7 14 (0.02 percent)..... 14 (0.02 percent).
jubatus).
California sea lion (Zalophus 7 7 7 7 14 (less than 0.001 14 (less than 0.001
californianus). percent). percent).
Gray whale (Eschrichtius robustus).. 1 1 1 1 2..................... 2
(less than 0.001 (less than 0.001
percent). percent).
Killer whale (Orcinus orca)......... 2
2 2 (0.5 2 (0.5
percent) percent).
--------------------------------------------------------------------
Harbor porpoise (Phocoena phocoena). 2 2 2 2 4 (0.008 percent)..... 4 (0.008 percent).
--------------------------------------------------------------------------------------------------------------------------------------------------------
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 (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) the practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
The following mitigation measures are included in the proposed
IHAs:
Timing Restrictions
All work will be conducted during daylight hours. If poor
environmental conditions restrict visibility full visibility of the
shutdown zone, pile installation would be delayed.
Shutdown Zone for In-Water Heavy Machinery Work
For in-water heavy machinery work other than pile driving, if a
marine mammal comes within 10 m of such operations, operations shall
cease and vessels shall reduce speed to the minimum level required to
maintain steerage and safe working conditions.
Shutdown Zones
For all pile driving/removal activities, the USACE will establish
shutdown zones for a marine mammal species that is greater than its
corresponding Level A harassment zone. To be conservative, the USACE is
proposing to implement one cetacean shutdown zone (55 m) and one
pinniped shutdown zone (25 m) during any pile driving/removal activity
(i.e., during sheet piles, H-piles, and 30-in steel pile installation
and removal) (Table 10) which exceeds the maximum calculated PTS
isopleths as described in Table 7. The purpose of a shutdown zone is
generally to define an area within which shutdown of the activity would
occur upon sighting of a marine mammal (or in anticipation of an animal
entering the defined area).
[[Page 56800]]
Table 10--Pile Driving Shutdown Zones During Project Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (radial distance in m, area in km\2*\)
----------------------------------------------------------------------------------------------
Activity Low-frequency Mid-frequency High-frequency
cetaceans cetaceans cetaceans Phocid Otariid
--------------------------------------------------------------------------------------------------------------------------------------------------------
In-Water Construction Activities:
Heavy machinery work (other than pile driving)........... 10 (0.00015) 10 (0.00015) 10 (0.00015) 10 (0.00015) 10 (0.00015)
Vibratory Pile Driving/Removal:
12-in H pile steel installation/removal.............. 55 (0.00475) 55 (0.00475) 55 (0.00475) 25 (0.00098) 25 (0.00098)
24-in sheet pile installation/removal................ 55 (0.00475) 55 (0.00475) 55 (0.00475) 25 (0.00098) 25 (0.00098)
30-in pile installation/removal...................... 55 (0.00475) 55 (0.00475) 55 (0.00475) 25 (0.00098) 25 (0.00098)
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: km\2\ were divided by two to account for land.
Non-Authorized Take Prohibited
If a species enters or approaches the Level B harassment zone and
that species is either not authorized for take or its authorized takes
are met, pile driving and removal activities must shut down immediately
using delay and shutdown procedures. Activities must not resume until
the animal has been confirmed to have left the area or an observation
time period of 15 minutes has elapsed for pinnipeds and small cetaceans
and 30 minutes for large whales.
Based on our evaluation of the USACE's proposed measures, NMFS has
preliminarily determined that the proposed mitigation measures provide
the means effecting the least practicable impact on the affected
species or stocks and their habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
[ssquf] Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
[ssquf] Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
[ssquf] Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
[ssquf] How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
[ssquf] Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
[ssquf] Mitigation and monitoring effectiveness.
Pre-Activity Monitoring
Prior to the start of daily in-water construction activity, or
whenever a break in pile driving of 30 min or longer occurs, PSOs will
observe the shutdown and monitoring zones for a period of 30 min. The
shutdown zone will be cleared when a marine mammal has not been
observed within the zone for that 30-min period. If a marine mammal is
observed within the shutdown zone, pile driving activities will not
begin until the animal has left the shutdown zone or has not been
observed for 15 min. If the Level B Harassment Monitoring Zone has been
observed for 30 min and no marine mammals (for which take has not been
authorized) are present within the zone, work can continue even if
visibility becomes impaired within the Monitoring Zone. When a marine
mammal permitted for Level B harassment take has been permitted is
present in the Monitoring zone, piling activities may begin and Level B
harassment take will be recorded.
Monitoring Zones
The USACE will establish and observe monitoring zones for Level B
harassment as presented in Table 8. The monitoring zones for this
project are areas where SPLs are equal to or exceed 120 dB rms (for
vibratory pile driving/removal). These zones provide utility for
monitoring conducted for mitigation purposes (i.e., shutdown zone
monitoring) by establishing monitoring protocols for areas adjacent to
the shutdown zones. Monitoring of the Level B harassment zones enables
observers to be aware of and communicate the presence of marine mammals
in the project area, and thus prepare for potential shutdowns of
activity. The USACE will also be gathering information to help better
understand the impacts of their proposed activities on species and
their behavioral responses.
Visual Monitoring
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all pile driving/removal activities. In addition, PSO
shall record all incidents of marine mammal occurrence, regardless of
distance from activity, and shall document any behavioral reactions in
concert with distance from piles being driven/removed. Pile driving/
removal activities include the time to install, remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than thirty minutes.
[[Page 56801]]
Monitoring will be conducted by PSOs from on land and boat. The
number of PSOs will vary from one to three, depending on the type of
pile driving, method of pile driving and size of pile, all of which
determines the size of the harassment zones. Monitoring locations will
be selected to provide an unobstructed view of all water within the
shutdown zone and as much of the Level B harassment zone as possible
for pile driving activities. During vibratory driving or removal of AZ-
sheets or H-piles, two PSOs will be present. One PSO will be located on
the shoreline adjacent to the MOF site or on the barge used for driving
piles. The other PSO will be boat-based and detect animals in the
water, along with monitoring the three haulout sites in the Level B
harassment zone (i.e., Pigeon Point, Clam Island/North Spit, and South
Slough). During vibratory driving and removal of steel pipe piles (30-
in), three PSOs will be present. As indicated above, one PSO will be on
the shoreline or barge adjacent to the MOF site. A second PSO will be
stationed near the South Slough haul out site, and the third PSO will
be boat-based and make observations while actively monitoring at and
between the two remaining haulout sites (i.e., Pigeon Point and Clam
Island).
In addition, PSOs will work in shifts lasting no longer than 4
hours with at least a 1-hour break between shifts, and will not perform
duties as a PSO for more than 12 hours in a 24[hyphen]hour period (to
reduce PSO fatigue).
Monitoring of pile driving shall be conducted by qualified, NMFS-
approved PSOs, who shall have no other assigned tasks during monitoring
periods. The USACE shall adhere to the following conditions when
selecting PSOs:
[ssquf] Independent PSOs shall be used (i.e., not construction
personnel);
[ssquf] At least one PSO must have prior experience working as a
marine mammal observer during construction activities;
[ssquf] Other PSOs may substitute education (degree in biological
science or related field) or training for experience;
[ssquf] Where a team of three or more PSOs are required, a lead
observer or monitoring coordinator shall be designated. The lead
observer must have prior experience working as a marine mammal observer
during construction; and
[ssquf] The USACE shall submit PSO CVs for approval by NMFS for all
observers prior to monitoring. The USACE shall ensure that the PSOs
have the following additional qualifications:
[ssquf] Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
[ssquf] Experience and ability to conduct field observations and
collect data according to assigned protocols;
[ssquf] Experience or training in the field identification of
marine mammals, including the identification of behaviors;
[ssquf] Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
[ssquf] Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior;
[ssquf] Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary; and
[ssquf] Sufficient training, orientation, or experience with the
construction operations to provide for personal safety during
observations.
Reporting of Injured or Dead Marine Mammals
In the unanticipated event that the planned activity clearly causes
the take of a marine mammal in a manner prohibited by the IHA, such as
serious injury, or mortality, the USACE must immediately cease the
specified activities and report the incident to the NMFS Office of
Protected Resources and the West Coast Region Stranding Coordinator.
The report must include the following information:
[ssquf] Time and date of the incident;
[ssquf] Description of the incident;
[ssquf] Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
[ssquf] Description of all marine mammal observations and active
sound source use in the 24 hours preceding the incident;
[ssquf] Species identification or description of the animal(s)
involved;
[ssquf] Fate of the animal(s); and
[ssquf] Photographs or video footage of the animal(s).
Activities must not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with USACE to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. The USACE may not
resume their activities until notified by NMFS.
In the event the USACE 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), the USACE must immediately report the
incident to the Office of Protected Resources, NMFS, and the West Coast
Region Stranding Coordinator, NMFS. The report must include the same
information as the bullets described above. Activities may continue
while NMFS reviews the circumstances of the incident. NMFS will work
with the USACE to determine whether additional mitigation measures or
modifications to the activities are appropriate.
In the event that the USACE 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 specified activities (e.g.,
previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), the USACE must report the incident
to the Office of Protected Resources, NMFS, and the West Coast Region
Stranding Coordinator, NMFS, within 24 hours of the discovery.
Final Report
The USACE shall submit a draft report to NMFS no later than 90 days
following the end of construction activities or 60 days prior to the
issuance of any subsequent IHA for the project. The USACE shall provide
a final report within 30 days following resolution of NMFS' comments on
the draft report. Reports shall contain, at minimum, the following:
[ssquf] Date and time that monitored activity begins and ends for
each day conducted (monitoring period);
[ssquf] Construction activities occurring during each daily
observation period, including how many and what type of piles driven;
[ssquf] Deviation from initial proposal in pile numbers, pile
types, average driving times, etc.;
[ssquf] Weather parameters in each monitoring period (e.g., wind
speed, percent cloud cover, visibility);
[ssquf] Water conditions in each monitoring period (e.g., sea
state, tide state);
[ssquf] For each marine mammal sighting:
[cir] Species, numbers, and, if possible, sex and age class of
marine mammals;
[[Page 56802]]
[cir] Number of individuals of each species (differentiated by
month as appropriate) detected within the monitoring zones, and
estimates of number of marine mammals taken, by species (a correction
factor may be applied to total take numbers, as appropriate);
[cir] Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity;
[cir] Type of construction activity that was taking place at the
time of sighting;
[cir] Location and distance from pile driving activities to marine
mammals and distance from the marine mammals to the observation point;
[cir] If shutdown was implemented, behavioral reactions noted and
if they occurred before or after shutdown.
[ssquf] Description of implementation of mitigation measures within
each monitoring period (e.g., shutdown or delay);
[ssquf] Other human activity in the area within each monitoring
period;
[ssquf] A summary of the following:
[cir] Total number of individuals of each species detected within
the Level B Harassment Zone, and estimated as taken if correction
factor appropriate;
[cir] Total number of individuals of each species detected within
the Level A Harassment Zone and the average amount of time that they
remained in that zone; and
[cir] Daily average number of individuals of each species
(differentiated by month as appropriate) detected within the Level B
Harassment Zone, and estimated as taken, if appropriate.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
To avoid repetition, the majority of our analyses applies to all
the species listed in Table 9, given that many of the anticipated
effects of this project on different marine mammal stocks are expected
to be relatively similar in nature. For harbor seals, because there is
thought to be a potential resident population and potential repeat
takes of individuals, we provide a supplemental analysis independent of
the other species for which we propose to authorize take. Also, because
both the number and nature of the estimated takes anticipated to occur
are identical in years 1 and 2, the analysis below applies to each of
the IHAs.
The USACE did not request, and NMFS is not proposing to authorize,
take in the form of injury, serious injury, or mortality. The nature of
the work precludes the likelihood of serious injury or mortality, and
the mitigation is expected to ensure that no Level A harassment occurs.
For all species and stocks, any take would occur within a limited,
confined area of any given stock's home range (Coos Bay). Take would be
limited to Level B harassment only. Exposure to noise resulting in
Level B harassment for all species is expected to be temporary and
minor due to the general lack of use of Coos Bay by cetaceans and
pinnipeds, as explained above. In general, cetacean and non-harbor seal
pinnipeds are infrequent visitors with only occasional sightings within
Coos Bay. Cetaceans such as transient killer whales may wander into
Coos Bay; however, any behavioral harassment occurring during the
project is highly unlikely to impact the health or fitness of any
individuals, much less effect annual rates of recruitment or survival,
given any exposure would be very brief with any harassment potential
from the project decreasing to zero once the animals leave the bay.
There are no habitat areas of particular importance for cetaceans
(e.g., biologically important area, critical habitat, primary foraging
or calving habitat) within Coos Bay. Further, the amount of take
proposed to be authorized for any given stock is very small when
compared to stock abundance, demonstrating that a very small percentage
of the stock would be affected at all by the specified activity.
Finally, while pile driving could occur year-round, pile driving would
be intermittent (not occurring every day) and primarily limited to the
MOF site, a very small portion of Coos Bay.
For harbor seals, the impact of harassment on the stock as a whole
is negligible given the stocks very large size (70,151 seals). However,
we are aware that it is likely a resident population of harbor seals
resides year round within Coos Bay. While this has not been
scientifically investigated through research strategies such as
tagging/mark-recapture techniques, anecdotal evidence suggests some
seals call Coos Bay home year-round, as suggested through AECOM's
winter surveys. The exact home range of this potential resident
population is unknown but harbor seals, in general, tend to have
limited home range sizes. Therefore, we can presume that some harbor
seals will be repeatedly taken. Repeated, sequential exposure to pile
driving noise over a longer duration could result in more severe
impacts to individuals that could affect a population; however, the
limited number of non-consecutive pile driving days for this project
means that these types of impacts are not anticipated. Further, these
animals are already exposed, and likely somewhat habituated, to
industrial noises such as USACE maintenance dredging, commercial
shipping and fishing vessel traffic (Coos Bay contains a major port),
and coastal development.
In summary, although this potential small resident population is
likely to be taken repeatedly, the impacts of that take are negligible
to the stock because the number of repeated days of exposure is small
(14 or fewer) and non-consecutive, the affected individuals represent a
very small subset of the stock that is already exposed to regular
higher levels of anthropogenic stressors, injurious noise levels are
not proposed for authorization, and the pile driving/removal would not
take place during the pupping season and during a time in which harbor
seal density is greatest.
The following factors primarily support our preliminary
determination that the impacts resulting from each of these two years
of activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
[[Page 56803]]
[ssquf] No serious injury or mortality is anticipated or
authorized;
[ssquf] No Level A harassment is anticipated or authorized;
[ssquf] The number and intensity of anticipated takes by Level B
harassment is relatively low for all stocks;
[ssquf] No biologically important areas have been identified for
the effected species within Coos Bay;
[ssquf] For all species, including the Oregon/Washington Coastal
stock of harbor seals, Coos Bay is a very small part of their range;
and
[ssquf] No pile driving would occur during the harbor seal pupping
season; therefore, no impacts to pups from this activity is likely to
occur.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from each of the two years of proposed activity will have a
negligible impact on all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
The take of seven marine mammal stocks proposed for authorization
comprises no more than 2.3 percent of any stock abundance.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, for each proposed IHA, 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. Therefore, for both
proposed IHAs, 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)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally, in this case with the West Coast Region
Protected Resources Division, whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed marine mammal species is proposed
for authorization or expected to result from this activity. Therefore,
NMFS has determined that formal consultation under section 7 of the ESA
is not required for this action.
Proposed Authorizations
As a result of these preliminary determinations, NMFS proposes to
issue two IHAs to USACE for pile driving and removal activities
associated with the North Jetty maintenance and repairs project in Coos
Bay, Oregon over the course of two non-consecutive years, beginning
September 2020 through June 2023, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
Drafts of the proposed IHAs can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHAs for the proposed pile
driving and removal activities associated with the USACE's North Jetty
maintenance and repairs project in Coos Bay, Oregon. We also request at
this time comment on the potential renewal of these proposed IHAs as
described in the paragraph below. Please include with your comments any
supporting data or literature citations to help inform decisions on the
request for these IHAs or a subsequent Renewal.
On a case-by-case basis, NMFS may issue a one-year IHA renewal with
an additional 15 days for public comments when (1) another year of
identical or nearly identical activities as described in the Specified
Activities section of this notice is planned or (2) the activities as
described in the Specified Activities section of this notice would not
be completed by the time the IHA expires and a second IHA would allow
for completion of the activities beyond that described in the Dates and
Duration section of this notice, provided all of the following
conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal are identical to the activities analyzed under the
initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take
because only a subset of the initially analyzed activities remain to be
completed under the Renewal).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: October 17, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2019-23081 Filed 10-22-19; 8:45 am]
BILLING CODE 3510-22-P
