Notice2025-13792
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Oregon Department of Transportation's Yaquina Bay Dolphin Replacement Project in Newport, Oregon
Primary source
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Published
July 22, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the Oregon Department of Transportation (ODOT) for authorization to take marine mammals incidental to construction activities for the Yaquina Bay Dolphin Replacement Project in Newport, Oregon. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in 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 authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 90 Issue 138 (Tuesday, July 22, 2025)</title>
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[Federal Register Volume 90, Number 138 (Tuesday, July 22, 2025)]
[Notices]
[Pages 34441-34461]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-13792]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE859]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Oregon Department of
Transportation's Yaquina Bay Dolphin Replacement Project in Newport,
Oregon
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Oregon Department of
Transportation (ODOT) for authorization to take marine mammals
incidental to construction activities for the Yaquina Bay Dolphin
Replacement Project in Newport, Oregon. Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is requesting comments on its proposal to
issue an incidental harassment authorization (IHA) to incidentally take
marine mammals during the specified activities. NMFS is also requesting
comments on a possible one-time, 1-year renewal that could be issued
under certain circumstances and if all requirements are met, as
described in 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 authorization and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than August
21, 2025.
ADDRESSES: Comments should be addressed to the Permits and Conservation
Division, Office of Protected Resources, NMFS and should be submitted
via email to <a href="/cdn-cgi/l/email-protection#430a17136d132c372f2c2028032d2c22226d242c35"><span class="__cf_email__" data-cfemail="c1889591ef91aeb5adaea2aa81afaea0a0efa6aeb7">[email protected]</span></a>. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In case of problems
accessing these documents, please call the contact listed below.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> 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: Kelsey Potlock, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et
seq.) directs the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on
[[Page 34442]]
the species or stock(s) and will not have an unmitigable adverse impact
on the availability of the species or stock(s) for taking for
subsistence uses (where relevant). Further, NMFS must prescribe the
permissible methods of taking and other ``means of effecting the least
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and requirements pertaining to the
monitoring and reporting of the takings. The definitions of all
applicable MMPA statutory terms used above are included in the relevant
sections below and can be found in section 3 of the MMPA (16 U.S.C.
1362) and NMFS regulations at 50 CFR 216.103.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment. This action
is consistent with categories of activities identified in Categorical
Exclusion B4 (IHAs with no anticipated serious injury or mortality) of
the Companion Manual for NAO 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has preliminarily determined that the
issuance of the proposed IHA qualifies to be categorically excluded
from further NEPA review.
Summary of Request
On March 12, 2025, NMFS received a request from ODOT for an IHA to
take marine mammals incidental to construction activities near the
Yaquina Bay Bridge in Newport, Oregon. Following NMFS' review of the
application, ODOT submitted revised versions on April 10, 2025 and May
16, 2025. The application was deemed adequate and complete on May 19,
2025. ODOT's request is for authorization of take of five species of
marine mammals, by Level B harassment only. Neither ODOT nor NMFS
expect serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
ODOT has requested an IHA to authorize marine mammal take
incidental to removing and subsequently installing new piles currently
being used as part of the pier protection system. The replacement piles
are intended to match the capacity and performance of the existing
piles. This project entails only coastal construction activities,
specifically pile removal and installation.
Presently, 33 steel piles, grouped in sets of 3 (referred to as a
``dolphin''), separate the channel from the Yaquina Bay Bridge's Pier
2. For the proposed project, ODOT, using a vibratory pile driver, would
remove all 33 steel piles making up the 11 dolphins and install 36 new,
16-inch (in) (40.64-centimeter (cm)) diameter, battered steel piles to
make up 12 new dolphin structures, consisting of groups of 3 steel
piles each.
Given the use of vibratory pile driving to both remove and install
the piles, there is potential for take of marine mammals by Level B
harassment only; no take by Level A harassment is expected nor proposed
for authorization for this project.
Dates and Duration
ODOT anticipates that this project would require up to 79 days of
work, with up to 46 of those days consisting of in-water activities
that could cause the take of marine mammals. Of this, 22 days are
estimated to be necessary for removal of the existing piles and 24 days
are estimated for the installation of replacement piles and piles for a
new dolphin structure. The remaining 33 days would be used for
mobilization and demobilization activities. All of the work for this
project is expected to occur between November 1, 2025, and February 15,
2026. The proposed construction schedule is shown in table 1.
[GRAPHIC] [TIFF OMITTED] TN22JY25.003
Specific Geographic Region
The proposed project would occur near the Yaquina Bay Bridge's Pier
2, located in Newport, Oregon near Yaquina Bay. Pier 2 is located on
the north side of the navigation channel (see figure 1).
[[Page 34443]]
[GRAPHIC] [TIFF OMITTED] TN22JY25.001
Figure 1--Project Location Near Yaquina Bay in Newport, Oregon
Detailed Description of the Specified Activity
ODOT proposes to remove and subsequently install piles currently
being used as part of the pier protection system. This proposed project
will include the removal of 11 dolphins, consisting of 33 piles via
vibratory pile driving and then the installation of 36 new 16-in
(40.64-cm) steel piles, which would make up 12 new dolphins. Piles will
all be ``battered,'' meaning the piles will be driven at an angle,
rather than vertically to provide for additional lateral resistance to
the overall structure. These replacement piles will be installed
somewhat offset from the existing dolphins to avoid driving piles in
previously disturbed sediment, as geotechnical engineers have confirmed
that replacing the dolphins in the same location as the existing piles
would require significantly deeper embedment to reach fixity. Pile
removal and driving will be accomplished utilizing equipment mounted on
a barge using supporting spuds. Piles will only require vibratory pile
driving and will not be proofed with an impact hammer.
Each pile (regardless of old or new status) is expected to take
approximately 45 minutes to remove or install. In total, ODOT's
engineers estimate that up to 8 hours of vibratory pile driving could
occur per day, but up to 2 days could be necessary to remove and
install each dolphin (which consists of three piles each). Up to 22
days are estimated to remove the 33 old piles and 24 days are estimated
to install the 36 new piles. While ODOT has allotted 79 workdays for
this activity (November 1, 2025, through February 15, 2026), only 46 of
those days are expected to require use of the vibratory hammer for pile
removal and/or installation (see table 2).
ODOT has also explained that the contractor may choose to remove
old piles and install the new piles within the same shift, rather than
removing all old piles and then installing all new piles. However, ODOT
clarified that only one vibratory hammer would be used and no two piles
would ever be driven at the same time.
Table 2--Pile Parameters for Removal and Installation via Vibratory Hammer
--------------------------------------------------------------------------------------------------------------------------------------------------------
Activity duration (minutes/per Maximum piles per day Total number of piles
pile) ---------------------------------------------------------------- Estimated
Pile size and type -------------------------------- number of days
Remove Install Remove Install Remove Install of work
--------------------------------------------------------------------------------------------------------------------------------------------------------
Old piles: 16-inch steel pile (battered) 45 .............. 3 .............. 33 .............. 22
New piles: 16-inch steel piles .............. 45 .............. 3 .............. 36 24
(battered).............................
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[[Page 34444]]
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 3 lists all species or stocks for which take is expected and
proposed to be authorized for ODOT's activities near Yaquina Bay, and
summarizes information related to the population or stock, including
regulatory status under the MMPA and Endangered Species Act (ESA) and
potential biological removal (PBR), where known. PBR is defined by the
MMPA as the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while
allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS' SARs). While no serious injury or
mortality is anticipated or proposed to be authorized here, PBR and
annual serious injury and mortality (M/SI) from anthropogenic sources
are included here as gross indicators of the status of the species or
stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates, for most species, represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' Alaska and Pacific SARs. All values presented in table 3 are the
most recent available at the time of publication (including from the
draft 2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 3--Species \a\ With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/ MMPA status; Stock abundance (CV;
Common name Scientific name Stock strategic (Y/N) Nmin; most recent PBR Annual M/
\b\ abundance survey) \c\ SI \d\
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Order Artiodactyla--Cetacea--Family Phocoenidae (porpoises):
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise.................... Phocoena phocoena..... Northern California/ -/-, N 15,303 (0.575; 9,759; 306 0
Southern Oregon. 2022).
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Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion............... Eumetopias jubatus.... Eastern DPS........... -/-, N 36,308 \e\ (N/A, 2,178 93.2
36,308, 2022).
California sea lion............ Zalophus californianus U.S................... -/-, N 257,606 (n/a; 14,011 >=321
233,515; 2014).
Family Phocidae (earless seals):
Harbor seal.................... Phoca vitulina Oregon/Washington -/-, N 22,549 \f\ (unknown; Undetermined 10.6
richardii. Coast. unknown; 1999.
Northern elephant seal......... Mirounga California Breeding... -/-, N 194,907 (n/a; 88,794; 5,328 11.2
angustirostris. 2023).
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\a\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy (2024)).
\b\ 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.
\c\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\d\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (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.
\e\ Nest is the best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the
United States only.
\f\ The abundance estimate for this stock is greater than 8 years old and is not considered current. PBR is considered undetermined for this stock, as
there is no current minimum abundance estimate for use in calculation. However, based on a recent scientific publication (Pearson et al., 2024) that
analyzes the status of harbor seals in Washington State, NMFS has substituted the estimated stock abundance to 22,549 from 24,731 animals based on the
best available information. Given Pearson et al. (2024) only covers the Washington portion of the Oregon/Washington, this is likely an underestimate.
As indicated above, all five species (with five managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While killer whales
(Orcinus orca), gray whales (Eschrichtius robustus), and humpback
whales (Megaptera novaeangliae) have been observed in the area, the
temporal and/or spatial occurrence of these species is such that take
is not expected to occur, and they are not discussed further beyond the
explanation provided here. Given mitigation planned by ODOT where the
project would experience either a delay or shutdown if one of these
species were observed, no take is expected to occur for these species.
For more details on the species that are likely to occur near the
project area and may be taken by ODOT's proposed activities, see ODOT's
IHA application, the draft SARs, and NMFS' website.
[[Page 34445]]
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 can hear. Not all marine mammal species have equal hearing
capabilities (e.g., Richardson et al., 1995; Wartzok and Ketten, 1999;
Au and Hastings, 2008). To reflect this, Southall et al. (2007, 2019)
recommended that marine mammals be divided into hearing groups based on
directly measured (behavioral or auditory evoked potential techniques)
or estimated hearing ranges (behavioral response data, anatomical
modeling, etc.). Generalized hearing ranges were chosen based on the
~65 decibel (dB) threshold from composite audiograms, previous analyses
in NMFS (2024), and/or data from Southall et al. (2007) and Southall et
al. (2019). We note that the names of two hearing groups and the
generalized hearing ranges of all marine mammal hearing groups have
been recently updated (NMFS, 2024), as reflected below in table 4.
Of the species that could be potentially taken in the proposed
project area, none are considered low-frequency (LF) cetaceans, three
are considered high-frequency (HF) cetaceans, one is considered very
high-frequency (VHF) cetaceans, two are otariid pinnipeds, and two are
phocid pinnipeds.
Table 4--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very high-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS (2018), and/or data from Southall et al. (2007) and
Southall et al. (2019). Additionally, animals are able to detect very
loud sounds above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated generalized
hearing ranges, please see (NMFS, 2024) for a review of available
information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and provides a discussion of the
ways in which components of the specified activity may impact marine
mammals and their habitat. The Estimated Take of Marine Mammals 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 of Marine Mammals section,
and the Proposed Mitigation section, to draw conclusions regarding the
likely impacts of these activities on the reproductive success or
survivorship of individuals and whether those impacts are reasonably
expected to, or reasonably likely to, adversely affect the species or
stock through effects on annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activities
are expected to potentially occur from vibratory pile removal and
installation. The effects of underwater noise from ODOT's proposed
activities have the potential to result in take by Level B harassment
of marine mammals in the project area.
Overall, the proposed activities include the removal of 33 and
installation of 36 piles near Yaquina Bay. There are a variety of types
and degrees of effects to marine mammals, prey species, and habitat
that could occur because of the proposed project. Below we provide a
brief description of the types of sound sources that would be generated
by the project, the general impacts from these types of activities, and
an analysis of the anticipated impacts on marine mammals from the
project, with consideration of the proposed mitigation measures.
Description of Sound Sources for the Specified Activities
Activities associated with the proposed project that have the
potential to incidentally take marine mammals though exposure to sound
would include vibratory pile removal and installation. Vibratory
hammers install piles by vibrating them and allowing the weight of the
hammer to push them into the substrate. Vibratory hammers typically
produce less sound (i.e., lower levels) than impact hammers. Peak sound
pressure levels (SPLs) may be 180 dB or greater, but are generally 10
to 20 dB lower than SPLs generated during impact pile driving of the
same-sized pile (Oestman et al., 2009; California Department of
Transportation (CALTRANS), 2015, 2020). Sounds produced by vibratory
hammers are non-impulsive; compared to sounds produced by impact
hammers, the rise time is slower, reducing the probability and severity
of injury, and the sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of ODOT's proposed activities on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, while there are two
pinniped haul-outs in the general area (i.e., the Finger Jetty Haul-Out
and the Bay Front Haul-Out), these are both over 495 meters (m) (1,624
feet (ft)) and 920 m (3,018 ft) from the project area, respectively.
Furthermore, existing ambient noise levels in the local area from day-
to-day activities (i.e., cars/trucks/traffic, boats, car/truck/traffic
horns, backup beepers from trucks, marina dock activity) are ongoing
and near-constant meaning the animals that haul-out in the area are
likely somewhat habituated to in-air stimuli. Given known conditions in
the environment, it is also likely that the perceived level of noise to
a marine mammal hauled out at the Finger Jetty would be lower as the
prevailing onshore winds would tend to dampen
[[Page 34446]]
noise propagation towards the southwest.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from vibratory pile driving is the primary means by which
marine mammals may be harassed from ODOT's specified activities.
Anthropogenic sounds cover a broad range of frequencies and sound
levels and can have a range of highly variable impacts on marine life
from none or minor to potentially severe responses depending on
received levels, duration of exposure, behavioral context, and various
other factors. Broadly, underwater sound from active acoustic sources,
such as those in the project, 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., 2003; Nowacek et al.,
2007; Southall et al., 2007; G[ouml]tz et al., 2009).
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly as we do not expect that
use of the vibratory hammer is reasonably likely to 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 project 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.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise has the potential to result in auditory threshold
shifts and behavioral reactions (e.g., avoidance, temporary cessation
of foraging and vocalizing, changes in dive behavior). It can also lead
to non-observable physiological responses, such an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection.
The degree of effect of an acoustic exposure on marine mammals is
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), signal characteristics, the
species, age and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the noise source and the
animal, received levels, behavioral state at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). In general, sudden, high-intensity sounds can cause hearing
loss, as can longer exposures to lower-intensity sounds. Moreover, any
temporary or permanent loss of hearing, if it occurs at all, will occur
almost exclusively for noise within an animal's hearing range. We
describe below the specific manifestations of acoustic effects that may
occur based on the activities proposed by ODOT.
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 (at the greatest distance) 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 (closer to the receiving animal) corresponds
with the area where the signal is audible to the animal and of
sufficient intensity to elicit behavioral or physiological
responsiveness. The 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.
Below, we provide additional detail regarding potential impacts on
marine mammals and their habitat from noise in general, starting with
hearing impairment, as well as from the specific activities ODOT plans
to conduct, to the degree it is available.
Hearing Threshold Shifts. NMFS defines a noise-induced threshold
shift (TS) as a change, usually an increase, in the threshold of
audibility at a specified frequency or portion of an individual's
hearing range above a previously established reference level (NMFS,
2018, 2024). The amount of threshold shift is customarily expressed in
dB. A TS can be permanent or temporary. As described in NMFS (2018,
2024) 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 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).
Auditory Injury (AUD INJ). NMFS (2024) defines AUD INJ as damage to
the inner ear that can result in destruction of tissue, such as the
loss of cochlear neuron synapses or auditory neuropathy (Houser, 2021;
Finneran, 2024). AUD INJ may or may not result in a permanent threshold
shift (PTS). PTS is subsequently defined 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, 2024). PTS does not generally affect more than a
limited frequency range, and an animal that has incurred PTS has some
level of hearing loss at the relevant frequencies; typically animals
with PTS or other AUD INJ are not functionally deaf (Au and Hastings,
2008; Finneran, 2016). Available data from humans and other terrestrial
mammals indicate that a 40-dB threshold shift approximates AUD INJ
onset (see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966;
Miller, 1974; Ahroon et al., 1996; Henderson et al., 2008). AUD INJ
levels for marine mammals are estimates, as with the exception of a
single study unintentionally inducing PTS in a harbor seal (Phoca
vitulina) (Kastak et al., 2008), there are no empirical data measuring
AUD INJ in marine mammals largely due to the fact that, for various
ethical reasons, experiments involving anthropogenic noise exposure at
levels inducing AUD INJ are not typically pursued or authorized (NMFS,
2024).
Temporary Threshold Shift (TTS). TTS is a temporary, reversible
increase
[[Page 34447]]
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2024), and is not considered an AUD INJ. Based on data
from marine mammal TTS measurements (see Southall et al., 2007, 2019),
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 (Finneran et al., 2000, 2002; Schlundt et al.,
2000). As described in Finneran (2015), marine mammal studies have
shown the amount of TTS increases with the 24-hour cumulative sound
exposure level (SEL<INF>24</INF>) in an accelerating fashion: at low
exposures with lower SEL<INF>24</INF>, the amount of TTS is typically
small and the growth curves have shallow slopes. At exposures with
higher SEL<INF>24</INF>, the growth curves become steeper and approach
linear relationships with the sound exposure level (SEL).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to more impactful (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 severe impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). 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. For
cetaceans, published data on the onset of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise (Phocoena phocoena), and Yangtze finless
porpoise (Neophocoena asiaeorientalis) (Southall et al., 2019). For
pinnipeds in water, measurements of TTS are limited to harbor seals
(Phoca vitulina), elephant seals (Mirounga angustirostris), bearded
seals (Erignathus barbatus) and California sea lions (Zalophus
californianus) (Kastak et al., 1999, 2007; Kastelein et al., 2019b,
2019c, 2021, 2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020).
TTS was not observed in spotted (Phoca largha) and ringed (Pusa
hispida) seals exposed to single airgun impulse sounds at levels
matching previous predictions of TTS onset (Reichmuth et al., 2016).
These studies examine hearing thresholds measured in marine mammals
before and after exposure to intense or long-duration sound exposures.
The difference between the pre-exposure and post-exposure thresholds
can be used to determine the amount of threshold shift at various post-
exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds below the region of best sensitivity for a species or hearing
group are less hazardous than those near the region of best sensitivity
(Finneran and Schlundt, 2013). At low frequencies, onset-TTS exposure
levels are higher compared to those in the region of best sensitivity
(i.e., a low frequency noise would need to be louder to cause TTS onset
when TTS exposure level is higher), as shown for harbor porpoises and
harbor seals (Kastelein et al., 2019a, 2019c). Note that in general,
harbor seals and harbor porpoises have a lower TTS onset than other
measured pinniped or cetacean species (Finneran, 2015). In addition,
TTS can accumulate across multiple exposures, but the resulting TTS
will be less than the TTS from a single, continuous exposure with the
same SEL (Mooney et al., 2009; Finneran et al., 2010; Kastelein et al.,
2014, 2015). This means that TTS predictions based on the total,
SEL<INF>24</INF> will overestimate the amount of TTS from intermittent
exposures, such as sonars and impulsive sources. Nachtigall et al.
(2018) describe measurements of hearing sensitivity of multiple
odontocete species (bottlenose dolphin, harbor porpoise, beluga
(Delphinapterus leucas), and false killer whale (Pseudorca crassidens)
when a relatively loud sound was preceded by a warning sound. These
captive animals were shown to reduce hearing sensitivity when warned of
an impending intense sound. Based on these experimental observations of
captive animals, the authors suggest that wild animals may dampen their
hearing during prolonged exposures or if conditioned to anticipate
intense sounds. Another study showed that echolocating animals
(including odontocetes) might have anatomical specializations that
might allow for conditioned hearing reduction and filtering of low-
frequency ambient noise, including increased stiffness and control of
middle ear structures and placement of inner ear structures (Ketten et
al., 2021). Data available on noise-induced hearing loss for mysticetes
are currently lacking (NMFS, 2024). Additionally, the existing marine
mammal TTS data come from a limited number of individuals within these
species.
Relationships between TTS and AUD INJ thresholds have not been
studied in marine mammals, and there are no measured PTS data for
cetaceans, but such relationships are assumed to be similar to those in
humans and other terrestrial mammals. AUD INJ typically occurs at
exposure levels at least several dB above that inducing mild TTS (e.g.,
a 40-dB threshold shift approximates AUD INJ onset (Kryter et al.,
1966; Miller, 1974), while a 6-dB threshold shift approximates TTS
onset (Southall et al., 2007, 2019). Based on data from terrestrial
mammals, a precautionary assumption is that the AUD INJ thresholds for
impulsive 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 AUD INJ cumulative sound exposure level
thresholds are 15 to 20 dB higher than TTS cumulative sound exposure
level thresholds (Southall et al., 2007, 2019). Given the higher level
of sound or longer exposure duration necessary to cause AUD INJ as
compared with TTS, it is considerably less likely that AUD INJ could
occur.
Behavioral Effects. Exposure to noise also has the potential to
behaviorally disturb marine mammals to a level that rises to the
definition of harassment under the MMPA. Generally speaking, NMFS
considers a behavioral disturbance that rises to the level of
harassment under the MMPA a non-minor response--in other words, not
every response qualifies as behavioral disturbance, and for responses
that do, those of a higher level, or accrued across a longer duration,
have the potential to affect foraging, reproduction, or survival.
Behavioral disturbance may
[[Page 34448]]
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 may include changing durations of surfacing and
dives, changing direction and/or speed; reducing/increasing vocal
activities; changing/cessation of certain behavioral activities (such
as socializing or feeding); eliciting a visible startle response or
aggressive behavior (such as tail/fin slapping or jaw clapping); and
avoidance of areas where sound sources are located. In addition,
pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National Research Council (NRC), 2005).
Controlled experiments with captive marine mammals have shown
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 (e.g.,
seismic airguns) have been varied but often consist of avoidance
behavior or other behavioral changes (Richardson et al., 1995; Morton
and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal (e.g., Erbe et al., 2019). 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. If a
sound source displaces marine mammals from an important feeding or
breeding area for a prolonged period, impacts on individuals and
populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005). However, there are broad categories of
potential response, which we describe in greater detail here, that
include alteration of dive behavior, alteration of foraging behavior,
effects to breathing, interference with or alteration of vocalization,
avoidance, and flight.
Avoidance and displacement. 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;
Blair et al., 2016). 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. Acoustic and movement bio-logging tools also have been used
in some cases to infer responses to anthropogenic noise. For example,
Blair et al. (2015) reported significant effects on humpback whale
foraging behavior in Stellwagen Bank in response to ship noise
including slower descent rates, and fewer side-rolling events per dive
with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes. 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.
Respiration rates vary naturally 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). For example, harbor porpoise respiration rates increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single
[[Page 34449]]
strike (SEL<INF>ss</INF>): 127 dB re 1 [mu]Pa\2\-s) (Kastelein et al.,
2013).
Avoidance is the displacement of an individual from an area or
migration path because of the presence of a sound or other stressors,
and is one of the most obvious manifestations of disturbance in marine
mammals (Richardson et al., 1995). For example, gray whales are known
to change direction--deflecting from customary migratory paths--in
order to avoid noise from seismic surveys (Malme et al., 1984). Harbor
porpoises, Atlantic white-sided dolphins (Lagenorhynchus actusus), and
minke whales (Balaenoptera acutorostrata) have demonstrated avoidance
in response to vessels during line transect surveys (Palka and Hammond,
2001). In addition, beluga whales in the St. Lawrence Estuary in Canada
have been reported to increase levels of avoidance with increased boat
presence by way of increased dive durations and swim speeds, decreased
surfacing intervals, and by bunching together into groups (Blane and
Jaakson, 1994). 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; Bowers et al., 2018). 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 (England et al., 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 fishes 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 5-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 (i.e., meaningful) 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.
Physiological 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., Selye,
1950; Moberg, 2000). In many cases, an animal's first and sometimes
most economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005; Ayres et al., 2012; Yang
et al., 2022). 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 (Eubalaena glacialis). In addition,
Lemos et al. (2022) observed a correlation between higher levels of
fecal glucocorticoid metabolite concentrations (indicative of a stress
response) and vessel traffic in gray whales. Yang et al. (2022) studied
behavioral and physiological responses in captive bottlenose dolphins
exposed to playbacks of ``pile-driving-like'' impulsive sounds, finding
significant changes in cortisol and other
[[Page 34450]]
physiological indicators but only minor behavioral changes. 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, 2005), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar construction projects.
Vocalizations and Auditory Masking. Since many marine mammals rely
on sound to find prey, moderate social interactions, and facilitate
mating (Tyack, 2008), noise from anthropogenic sound sources can
interfere with these functions, but only if the noise spectrum overlaps
with the hearing sensitivity of the receiving marine mammal (Southall
et al., 2007; Clark et al., 2009; Hatch et al., 2012). Chronic exposure
to excessive, though not high-intensity, noise could cause masking at
particular frequencies for marine mammals that utilize sound for vital
biological functions (Clark et al., 2009). Acoustic masking is when
other noises such as from human sources interfere with 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). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environments
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. 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 (Hotchkin and
Parks, 2013).
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) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic 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). Fin whales (Balaenoptera physalus) have also been
documented lowering the bandwidth, peak frequency, and center frequency
of their vocalizations under increased levels of background noise from
large vessels (Castellote et al., 2012). Other alterations to
communication signals have also been observed. For example, gray
whales, in response to playback experiments exposing them to vessel
noise, have been observed increasing their vocalization rate and
producing louder signals at times of increased outboard engine noise
(Dahlheim and Castellote, 2016). Alternatively, in some cases, animals
may cease sound production during production of aversive signals
(Bowles et al., 1994, Wisniewska et al., 2018).
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 human-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 (though not necessarily one
that would be associated with harassment).
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, 2010; 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, including modifications of the acoustic
properties of the signal or the signaling behavior (Hotchkin and Parks,
2013). 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).
Since noises generated from the proposed construction activities
are mostly concentrated at low frequencies (<2 kHz), these activities
likely have less effect on mid-frequency echolocation sounds produced
by odontocetes (toothed whales). However, lower frequency noises are
more likely to affect detection of communication calls and other
potentially important natural sounds such as surf and prey noise. Low-
frequency noise may also affect communication signals when they occur
near the frequency band for noise and thus reduce the communication
space of animals (e.g., Clark et al., 2009) and cause increased stress
levels (e.g., Holt et al., 2009). Unlike TS, masking, which can occur
over large temporal and spatial scales, can potentially affect the
species at population, community, or even ecosystem levels, in addition
to individual levels. Masking affects both senders and receivers of the
signals, and at higher levels for longer durations, could have long-
term chronic effects on marine mammal species and populations. However,
the noise generated by ODOT's proposed activities will only occur
intermittently, across an estimated 46 days during the proposed
authorization period in a relatively small area focused around the
proposed construction site. Thus, while ODOT's proposed activities may
mask some acoustic signals that are relevant to the daily behavior of
marine mammals, the short-term duration and limited areas affected make
it very unlikely that the fitness of individual marine mammals would be
impacted.
While in some cases marine mammals have exhibited little to no
obviously detectable response to certain common or routine
industrialized activities (Cornick et al., 2011; Horsley and Larson,
2023), it is possible some animals may at times be exposed to
[[Page 34451]]
received levels of sound above the Level B harassment thresholds during
the proposed project. This potential exposure in combination with the
nature of planned activity (e.g., vibratory pile driving) means it is
possible that take by Level B harassment could occur over the total
estimated period of activities; therefore, NMFS, in response to the
ODOT's IHA application, proposes to authorize take by Level B
harassment from the ODOT's proposed construction activities.
Airborne Acoustic Effects. Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with construction
activities that have the potential to cause behavioral harassment,
depending on their distance from these activities. Airborne noise would
primarily be an issue for pinnipeds that are swimming or hauled out
near the project site within the range of noise levels elevated above
airborne acoustic harassment criteria. Although pinnipeds are known to
haul-out regularly on man-made objects, we believe that incidents of
take resulting solely from airborne sound are unlikely due to the
proximity between the proposed project area and the known haul-out
sites (e.g., the Finger Jetty Haul-Out (approximately 495 m from the
project area) and the Bay Front Haul-Out (approximately 920 m from the
project area)). Cetaceans are not expected to be exposed to airborne
sounds that would result in harassment as defined under the MMPA.
We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to flush from haul-outs,
temporarily abandon the area, and or move further from the source.
ODOT's calculations demonstrate that the in-air sound levels will
attenuate with distance and will not exceed the 90-100 dB RMS
behavioral disruption threshold for marine mammals exposed to in-air
noise (table 5). Calculations show that worse-case construction-related
in-air sound level (89 A-weighted decibels (dBA) at 15 meters) will be
attenuated to 75.4 dB RMS (58.8 dBA) at the Finger Jetty haul-out
located 495 m (1,624.02 ft) to the southwest and to 73.4 dB RMS (53.4
dBA) at the Bay Front haul-out located 920 m (3,018.37 ft) away from
the project area. Overall, in-air noise generated at the project area
is expected to remain well below behavioral harassment thresholds for
marine mammals and not expected to cause harassment to animals that may
be hauled out in or around Yaquina Bay.
Table 5--In-Air Noise Levels From Construction Equipment and Common
Local Noise Sources
------------------------------------------------------------------------
Peak value (dBA) at Take of marine
Equipment 15 meters mammals expected?
------------------------------------------------------------------------
Construction noise sources
------------------------------------------------------------------------
Crane/derrick \a\.............. 89................. No.
Hand tools \a\................. 85................. No.
Generator \a\.................. 77................. No.
Vibratory pile driver.......... Average 99......... No.
------------------------------------------------------------------------
Common/daily noise sources
------------------------------------------------------------------------
Cars/trucks \b\................ 88................. No.
Boats \b\...................... 75................. No.
Car/truck horns/backup beepers 107................ No.
\b\.
Marina dock activity \b\....... 88................. No.
------------------------------------------------------------------------
\a\ Anticipated construction equipment used (from the ODOT noise
manual).
\b\ Existing local noises not related to construction.
Furthermore, these animals would previously have been `taken'
because of exposure to underwater sound above the behavioral harassment
thresholds, which are in all cases larger than those associated with
airborne sound. Thus, the behavioral harassment of these animals is
already accounted for in these estimates of potential take. Therefore,
we do not believe that authorization of incidental take resulting from
airborne sound for pinnipeds is warranted, and airborne sound is not
discussed further here.
Potential Effects on Marine Mammal Habitat
ODOT's proposed activities could have localized, temporary impacts
on marine mammal habitat, including prey, by increasing in-water SPLs.
Increased noise levels may affect acoustic habitat and adversely affect
marine mammal prey near the project area (see discussion below).
Elevated levels of underwater noise would ensonify the project areas
where both fishes and mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during the proposed
construction activities; however, displacement due to noise is expected
to be temporary and is not expected to result in long-term effects to
the individuals or populations.
The total area likely impacted by ODOT's activities is relatively
small compared to the available habitat in and around Yaquina Bay.
Avoidance by potential prey (i.e., fish) of the immediate area due to
increased noise is possible. The duration of fish and marine mammal
avoidance of this area after tugging stops is unknown, but a rapid
return to normal recruitment, distribution, and behavior is
anticipated. Any behavioral avoidance by fish or marine mammals of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity.
The proposed project will occur within the approximate footprint of
existing marine infrastructure. The nearshore and intertidal habitat
where the proposed project will occur is an area of relatively high
marine vessel traffic. Most marine mammals do not generally use the
area within the
[[Page 34452]]
footprint of the project area. Temporary, intermittent, and short-term
habitat alteration may result from increased noise levels during the
proposed construction activities. Effects on marine mammals will be
limited to temporary displacement from pile installation and removal
noise, and effects on prey species will be similarly limited in time
and space.
Water quality. Temporary and localized reduction in water quality
will occur because of in-water construction activities. Most of this
effect would occur during the installation and removal of piles when
bottom sediments are disturbed. The installation and removal of piles
using the vibratory hammer would disturb bottom sediments and may cause
a temporary increase in suspended sediment in the project area. During
pile extraction, sediment attached to the pile moves vertically through
the water column until gravitational forces cause it to slough off
under its own weight. The small resulting sediment plume is expected to
settle out of the water column within a few hours. Studies of the
effects of turbid water on fish (marine mammal prey) suggest that
concentrations of suspended sediment can reach thousands of milligrams
per liter before an acute toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Following the completion of sediment-
disturbing activities, suspended sediments in the water column should
dissipate and quickly return to background levels in all construction
scenarios. Turbidity within the water column has the potential to
reduce the level of oxygen in the water and irritate the gills of prey
fish species in the proposed project area. However, turbidity plumes
associated with the project would be temporary and localized, and fish
in the proposed project area would be able to move away from and avoid
the areas where plumes may occur. Therefore, it is expected that the
impacts on prey fish species from turbidity, and therefore on marine
mammals, would be minimal and temporary. In general, the area likely
impacted by the proposed construction activities is relatively small
compared to the available marine mammal habitat in and around Yaquina
Bay.
Potential Effects on Prey. Sound may affect marine mammals through
impacts on the abundance, behavior, or distribution of prey species
(e.g., crustaceans, cephalopods, fishes, and zooplankton). Marine
mammal prey varies by species, season, and location and, for some, is
not well documented. Studies regarding the effects of noise on known
marine mammal prey are described here.
Fishes 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 that are especially strong and/or intermittent
low-frequency sounds and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fishes (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.,
Pe[ntilde]a et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman,
2009; Cott et al., 2012). More commonly, though, the impacts of noise
on fishes are temporary.
SPLs of sufficient strength have been known to cause injury to
fishes and fish mortality (summarized in Popper et al., 2014). 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. (2012b) showed that a TTS of
4 to 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.,
2012a; Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation and removal. The frequency range in which fishes generally
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution
may change, especially with strong and/or intermittent sounds that
could harm fishes. High underwater SPLs have been documented to alter
behavior, cause hearing loss, and injure or kill individual fish by
causing serious internal injury (Hastings and Popper, 2005).
In-water construction activities would only occur during daylight
hours, allowing fish to forage and transit the project area in the
evening. Vibratory pile driving would possibly elicit behavioral
reactions from fishes such as temporary avoidance of the area but is
unlikely to cause injuries to fishes or have persistent effects on
local fish populations. Construction is expected to have minimal
permanent and temporary impacts on benthic invertebrate species, which
are known marine mammal prey source. In addition, the area in question
is generally considered low-quality habitat since it is already highly
developed and experiences a high level of anthropogenic noise from
normal operations and other vessel traffic.
Potential Effects on Foraging Habitat
This proposed project is not expected to result in any habitat
related effects that could cause significant or long-term negative
consequences for individual marine mammals or their populations, since
installation and removal of in-water piles would be temporary and
intermittent. The total seafloor area affected by pile installation and
removal is a very small area compared to the vast foraging area
available to marine mammals outside this project area, and no areas of
particular importance would be affected by this project during the
period planned for activities to occur (i.e., November through
February). For gray whales, Yaquina Bay and the oceanfront areas
directly outside of the bay have known seasonal value as a Biologically
Important Area (BIA)
[[Page 34453]]
feeding area, with (from June to November; Harrison et al., 2023). In
addition to known foraging habitat, areas directly outside of Yaquina
Bay (ocean-side) also serve as both migratory and reproductive habitat
for this species (Harrison et al., 2023). For other species, while the
area is commonly used or traversed, the proposed project area does not
contain any particularly high-value habitat and is not usually
important to any of the other species potentially affected by ODOT's
proposed activities. 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 the ODOT's construction to affect the
availability of prey to marine mammals or to meaningfully affect the
quality of physical or acoustic habitat is considered insignificant.
Therefore, impacts of the project are not likely to have adverse
effects on marine mammal foraging habitat in the proposed project area.
In summary, given the relatively small areas being affected, as
well as the temporary and mostly transitory nature of the proposed
construction activities, any adverse effects from ODOT's activities on
prey habitat or prey populations are expected to be minor and
temporary. The most likely impact to fishes at the project site would
be temporary avoidance of the area. 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. Thus, we
conclude that impacts of the specified activities are not likely to
have more than short-term adverse effects on any prey habitat or
populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of behavioral reactions for individual marine mammals resulting from
exposure to vibratory pile driving. Based on the nature of the activity
and the anticipated effectiveness of the proposed mitigation measures
(i.e., enhanced shutdown zone around the approximate 28 m (92.9 ft)
distance to the Level A harassment threshold) discussed in detail below
in the Proposed Mitigation section, Level A harassment is neither
anticipated nor proposed to be authorized. Additionally, as described
previously, no serious injury or mortality is anticipated or proposed
to be authorized for this activity. Below we describe how the proposed
take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes the best
available science indicates marine mammals will likely be behaviorally
harassed or incur some degree of AUD INJ; (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria 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 AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS,
2024) as reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
ODOT's proposed construction includes the use of continuous
(vibratory pile driving) sources, and therefore the RMS SPL thresholds
of 120 dB re 1 [mu]Pa is applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (NMFS, 2024) identifies dual criteria to assess AUD INJ (Level A
harassment) to five different underwater marine mammal groups (based on
hearing sensitivity) as a result of exposure to noise from two
different types of sources (impulsive or non-impulsive)
[[Page 34454]]
(table 6). ODOT's proposed construction includes the use of a non-
impulsive (vibratory pile driving) source.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in table 6. The references, analysis, and
methodology used in the development of the criteria are described in
NMFS' 2024 Updated Technical Guidance, which may be accessed at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 6--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak SPL criteria
associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-impulsive
sources.
Note: Peak SPL (Lp,0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound exposure level (LE,p)
has a reference value of 1 [mu]Pa\2\s. In this table, criteria are abbreviated to be more reflective of
International Organization for Standardization standards (ISO 2017; ISO 2020). The subscript ``flat'' is being
included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing range
of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound exposure
level criteria indicates the designated marine mammal auditory weighting function (LF, HF, and VHF cetaceans,
and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted cumulative
sound exposure level criteria 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 criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the proposed project area is the existing
background noise and any additional construction noise produced from
the proposed project. Marine mammals are only expected to potentially
be taken by sound generated by vibratory pile driving). The source
level assumed for both removal and installation activities is based on
reviews of measurements of the same or similar types and dimensions of
piles available in the literature and from similar coastal construction
projects. The source level for the piles and activity are presented in
table 7. The source level for vibratory removal and installation of
piles of the same material and diameter are assumed to be the same.
Table 7--Estimates of Underwater Sound Levels Generated During Vibratory Pile Driving
[Removal and installation]
----------------------------------------------------------------------------------------------------------------
Proxy sound source levels at 10 m (dB re 1
[mu]Pa)
Pile size and method Activity ------------------------------------------------ Reference
RMS SPL SEL Peak
----------------------------------------------------------------------------------------------------------------
16-inch steel pile; vibratory Removal........ 163 .............. .............. NMFS (2023).
16-inch steel pile; vibratory Installation... 163 .............. .............. NMFS (2023).
----------------------------------------------------------------------------------------------------------------
Transmission Loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B x Log10(R1/R2),
Where:
TL = transmission loss in dB,
B = transmission loss coefficient,
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for Yaquina Bay is not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the
[[Page 34455]]
best way to estimate isopleth distances when more sophisticated
modeling methods are not available or practical. For stationary
sources, such as vibratory pile driving, the optional User Spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur auditory injury. Inputs used in the optional User Spreadsheet
tool, and the resulting estimated isopleths, are reported below in
tables 8 and 9.
Table 8--NMFS User Spreadsheet Variables and Inputs
------------------------------------------------------------------------
User Spreadsheet Variables and Inputs
-------------------------------------------------------------------------
A.1) Vibratory
Spreadsheet tab used pile driving
------------------------------------------------------------------------
Sound Pressure Level (dB)............................. 163
Distance associated with sound pressure level (meters) 10
Transmission loss coefficient......................... 15
Number of piles removed/installed per day............. 3
Duration to drive each pile (minutes)................. 45
Duration of sound production in a day (seconds)....... 8,100
Marine mammal Weighting Factor Adjustment (WFA) (kHz). 2.5
Cumulative SEL at measured distance................... 202
------------------------------------------------------------------------
Table 9--Distances to the Level A Harassment and Level B Harassment Thresholds From Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
Level A harassment Level B harassment
---------------------------------------------------------------
Species group Current Distance to Current Distance to
threshold (dB; threshold threshold (dB; threshold
SELcum) (meters) SPLRMS) (meters)
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans......................... 197 21.5 120 \a\ 7,356.4
High-frequency cetaceans........................ 201 8.3 \b\ (2,500)
Very high-frequency cetaceans................... 181 17.6
Phocid pinnipeds (in water)..................... 195 27.7
Otariid pinnipeds (in water).................... 199 9.3
----------------------------------------------------------------------------------------------------------------
\a\ Distances represent the calculated radius of the zone. The actual zone may be truncated by landforms.
\b\ The Level B harassment zone has been adjusted downward to account for the presence of jetties in the project
area, which are expected to have a sound reduction effect.
Notably, the calculated distance to the Level B harassment
threshold was calculated by ODOT as 7,356.4 m (4.57 miles (mi)).
However, based on the known interactions of sound pressure levels at
varying depths, with bubbles, and with jetty walls (Erbe et al., 2022),
it was assumed that the noise would scatter, reduce the intensity of
the sound, and affect the propagation of the sound waves through the
navigation channel. ODOT manually calculated the presence of the
seaward jetties to have a dampening effect on the noise levels to a
distance of 2,260 m (1.4 mi), which was rounded up to 2,500 m (1.55
mi).
Marine Mammal Occurrence and Take Estimation
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information, which
will inform the take calculations. Next, we describe how all of the
information described above is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and proposed
for authorization.
ODOT provided estimated group sizes and count information based on
data from marine mammal specialists at the Oregon Department of Fish &
Wildlife (ODFW) in Newport, Oregon. NMFS evaluated these numbers in
comparison to eight other projects in Oregon (i.e., 90 FR 13582, March
25, 2025; 87 FR 50836, August 18, 2022; 89 FR 79557, September 30,
2024; 89 FR 89543, November 13, 2024; 88 FR 77985, November 14, 2023;
85 FR 1140, January 9, 2020; 83 FR 19243, May 2, 2018; and 82 FR 10286,
February 10, 2017). These values are based on survey/sighting effort/
expertise by ODOT, ODFW, and NMFS and represent the most accurate
information regarding marine mammal occurrence in and around Yaquina
Bay. These values are shown in table 10.
Table 10--Estimated Occurrence of Marine Mammals In and Around Yaquina
Bay
------------------------------------------------------------------------
Estimated
number for
Species (common name) group size/
count
------------------------------------------------------------------------
Harbor porpoise......................................... 2
Steller sea lion........................................ 2
California sea lion..................................... 500
Harbor seal............................................. 60
Northern elephant seal.................................. 0.5
------------------------------------------------------------------------
To calculate the take, by Level B harassment only, that is expected
to occur from ODOT's proposed activities, we multiplied the estimated
days of in-water activities (for which the vibratory hammer would be
used; n=46) by the associated group size/occurrence estimates provided
by ODOT. This yielded the proposed values shown in table 11.
[[Page 34456]]
Table 11--Proposed Take, by Level B Harassment Only, by Stock, Harassment Type, and as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated days of work
Estimated Estimated group -------------------------------- Proposed takes Proposed stock
Species (common name) \a\ Stock stock size per day Days of noise by Level B percentage to
abundance (table 10) Total \b\ exposure \b\ harassment \c\ be taken
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise................. Northern 15,303 2................. 79 46 92 0.6
California/
Southern Oregon.
Steller sea lion................ Eastern DPS....... 36,308 2................. 79 46 92 0.25
California sea lion............. U.S............... 257,606 500............... 79 46 23,000 8.93
Harbor seal..................... Oregon/Washington 22,549 60................ 79 46 2,760 12.24
coast.
Northern elephant seal.......... California 194,907 0.5 (one 79 46 23 0.01
breeding. individual
assumed present
on half of the
days).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ As previously described, no take was requested for gray whales, humpback whales, or killer whales as the applicant intends to shut down if any are
observed near the project area. Therefore, no take has been proposed for authorization and these species are not shown here.
\b\ The total number of in-water workdays are shown as a comparison; only 46 days would consist of activities that could cause the take of marine
mammals so this value is used in the take estimate calculation.
\c\ As previously stated, no take by Level A harassment is expected so none is proposed for authorization here.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
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, and impact on
operations.
In addition to the measures described later in this section, ODOT
would be required to follow these general mitigation measures:
<bullet> Take proposed to be authorized, by Level B harassment
only, would be limited to the species and numbers listed in tables 3
and 11. Proposed construction activities must be halted upon
observation of either a species for which incidental take would not be
authorized or a species for which incidental take would be authorized
but the authorized number of takes has been met, entering or is within
the harassment zone;
<bullet> The taking by Level A harassment, serious injury, or death
of any of the species listed in tables 3 and 11 or any taking of any
other species of marine mammal would be prohibited and would result in
the modification, suspension, or revocation of the IHA, if issued. Any
taking exceeding the authorized amounts listed in table 11 would be
prohibited and would result in the modification, suspension, or
revocation of the IHA, if issued;
<bullet> Ensure that construction supervisors and crews, the marine
mammal monitoring team, and relevant ODOT staff are trained prior to
the start of all construction activities, so that responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures are clearly understood. New personnel joining
during the project must be trained prior to commencing work;
<bullet> ODOT, construction supervisors and crews, Protected
Species Observers (PSOs), and relevant project staff must avoid direct
physical interaction with marine mammals during construction activity.
If a marine mammal comes within 10 m (32.8 ft) of such activity,
operations must cease and vessels must reduce speed to the minimum
level required to maintain steerage and safe working conditions, as
necessary to avoid direct physical interaction; and
<bullet> Employ PSOs and establish monitoring locations as
described in section 5 of the IHA and ODOT's Marine Mammal Monitoring
Plan (see the proposed plan found on NMFS' website: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>). ODOT would be required to
monitor the project area to the maximum extent possible based on the
required number of PSOs, required monitoring locations, and
environmental conditions.
Additionally, the following mitigation measures apply to ODOT's in-
water construction activities.
Pre- and Post-Activity Monitoring
ODOT would be required to establish pre- and post-monitoring zones
with radial distances (based on the distances to the Level B harassment
threshold), as identified in table 12, for all construction activities.
All pre-start clearance monitoring must be conducted during periods of
visibility sufficient for the PSO to determine that the shutdown zones
indicated in table 12 are clear of marine mammals. All monitoring would
be required to take place from 30 minutes prior to initiation of pile
driving activity (i.e., pre-clearance monitoring) through 30 minutes
post-completion of pile driving activity. Pile driving may commence
following 30 minutes of observation when the determination is made that
the shutdown zones are clear of marine mammals (see table 13 further
below).
[[Page 34457]]
Table 12--Proposed Monitoring Zones During ODOT's Construction
Activities
------------------------------------------------------------------------
Proposed Level B
harassment
Activity monitoring zones
for all marine
mammals (meters)
------------------------------------------------------------------------
Vibratory Pile Removal and Installation............. 2,500
------------------------------------------------------------------------
If a break in vibratory pile driving occurs for a duration of 30
minutes or longer, ODOT must begin the 30 minute pre-clearance
monitoring again to ensure the applicable monitoring zones are clear of
marine mammals.
Soft-Start
Soft-start would not be required during the proposed vibratory pile
driving activities for the installation or removal of in-water piles.
Shutdown Zones
ODOT would be required to establish shutdown zones with radial
distances, as identified in table 13, for all construction activities.
The purpose of a shutdown zone is generally to define an area within
which shutdown of the activity would occur upon sighting of a marine
mammal (or in anticipation of an animal entering the defined area). The
shutdown zone during vibratory pile driving is based on the greatest
distance to Level A harassment threshold (i.e., 27.7 m (90.9 ft) (refer
back to table 9)), initially rounded up to the nearest whole number (28
m (91.9 ft)).
PSOs will be stationed at various land-based observations points
during the proposed construction activities and will monitor
continuously during in-water work. If a marine mammal is observed
entering or within the shutdown zones indicated in table 13, pile
driving activity must be delayed or halted. If pile driving is delayed
or halted due to the presence of a marine mammal, the activity may not
commence or resume until either the animal has voluntarily exited and
been visually confirmed beyond the shutdown zones or 15 minutes have
passed without re-detection of the animal. If a marine mammal comes
within or approaches the shutdown zone indicated in table 13, such
operations must cease.
Table 13--Proposed Shutdown Zones During ODOT's Construction Activities
------------------------------------------------------------------------
Proposed
Level A
harassment
Activity shutdown
zone
(meters)
------------------------------------------------------------------------
Vibratory pile removal and installation.................... \a\ 28
Other in-water work (non-noisy)............................ 10
------------------------------------------------------------------------
\a\ This represents the greatest distance calculated to the Level A
harassment threshold for marine mammals, rounded up to the nearest
whole number.
If a marine mammal species for which take is not authorized by this
IHA, if issued, enters the harassment zone, all in-water activities
would cease until the animal leaves the zone or has not been observed
for at least 15 minutes. ODOT would then be required to notify NMFS
about the species and precautions taken. Vibratory pile driving would
proceed if the non-IHA species is observed to leave the Level B
harassment zone or if 15 minutes have passed since the last
observation.
Monitoring Zone During Construction Activities
All marine mammals would be monitored in the Level B harassment
zone and throughout the area as far as visual monitoring can take
place. If a marine mammal enters the Level B harassment zone, in-water
activities would continue and the animal's presence within the
estimated harassment zone would be documented.
Based on our evaluation of the proposed mitigation measures, NMFS
has preliminarily determined that the measures provide the means of
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical, for both
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
ODOT would be required to abide by all monitoring and reporting
measures contained within the IHA, if issued, and their Marine Mammal
Monitoring Plan (see the proposed plan found on NMFS' website: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>). A summary of those
measures, and additional requirements proposed by NMFS, is described
below.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
conditions in this section and the IHA, if issued. Marine mammal
monitoring during vibratory pile driving activities would be conducted
by PSOs who meet the following requirements:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods;
[[Page 34458]]
<bullet> At least one PSO would have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
<bullet> Other PSOs may substitute relevant experience, education
(degree in biological science or related field), or training for prior
experience performing the duties of a PSO during construction activity
pursuant to a NMFS-issued incidental take authorization; and
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator would be designated. The lead
observer would be required to have prior experience performing the
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization.
PSOs must also have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
For this project, ODOT biologists would fulfil the duties of PSOs,
as long as they receive the appropriate level of training and meet the
qualifications described herein. NMFS has determined that these
personnel would meet the aforementioned requirement for independent
PSOs. ODOT would be required to establish monitoring locations as
described in the Marine Mammal Monitoring Plan (see the proposed plan
found on NMFS' website: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>). For all pile driving activities, a minimum of two PSOs and
one Department of Transportation inspector would be assigned to the
active pile driving location (i.e., onsite) to monitor the shutdown
zones. One of these PSOs will be stationed at the best practicable
land-based vantage point to observe the eastern portion of Yaquina Bay
and the designated Level A shutdown zones directly around the work
area. The other PSO will be positioned at the best practicable land-
based vantage point to monitor the western (seaward) portion of the
monitoring zones (see figure 2). Additional ODOT construction
inspector(s) may also be on-site during all pile removal activities to
ensure contract specifications are followed and to ensure that all
radio communications from PSOs are implemented. PSOs would record all
observations of marine mammals, regardless of distance from the pile
being driven, as well as the additional data indicated below and in
section 6 of the IHA, if issued.
[GRAPHIC] [TIFF OMITTED] TN22JY25.002
Figure 2--Proposed PSO Monitoring Locations (Gray Dots) During
Vibratory Pile Driving Activities for the Yaquina Bay Dolphin
Replacement Project
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. All PSOs would have
access to high-quality binoculars and/or spotting scopes to monitor
distances, and two-way radios for maintaining contact with work crews,
ODOT inspectors, and other PSOs. In addition, PSOs would record all
incidents of marine mammal occurrence, regardless of distance from the
construction activities, and would document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or
[[Page 34459]]
remove a single pile or series of piles, as long as the time elapsed
between uses of the pile driving equipment is no more than 30 minutes.
ODOT shall conduct briefings between construction supervisors and
crews, PSOs, ODOT staff prior to the start of all pile driving
activities and when new personnel join the work. These briefings would
explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
Reporting
ODOT would be required to submit an annual draft summary report on
all construction activities and marine mammal monitoring results to
NMFS within 90 days following the end of construction or 60 calendar
days prior to the requested issuance of any subsequent IHA for similar
activity at the same location, whichever comes first. The draft summary
report would include an overall description of construction work
completed, a narrative regarding marine mammal sightings, and
associated raw PSO data sheets (in electronic spreadsheet format).
Specifically, the report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (a) how many and what type of piles were
driven or removed; (b) the method of removal and installation (i.e.,
vibratory pile driving); and (c) the total duration of time needed to
drive each pile via vibratory driving;
<bullet> PSO locations during marine mammal monitoring; and
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance.
Upon observation of a marine mammal the following information must
be reported:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at the time of the sighting;
<bullet> Time of the sighting;
<bullet> Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
<bullet> Distance and bearing of each observed marine mammal
relative to the pile being driven or removed for each sighting;
<bullet> Estimated number of animals (min/max/best estimate);
<bullet> Estimated number of animals by cohort (e.g., adults,
juveniles, neonates, group composition, etc.);
<bullet> Animal's closest point of approach and estimated time
spent within the estimated harassment zone(s);
<bullet> Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
<bullet> Number of marine mammals detected within the estimated
harassment zones, by species; and
<bullet> Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specified
actions that ensured, and resulting changes in behavior of the
animal(s), if any.
If no comments are received from NMFS within 30 days after the
submission of the draft summary report, the draft report would
constitute the final report. If ODOT received comments from NMFS, a
final summary report addressing NMFS' comments must be submitted within
30 days after receipt of comments.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in ODOT's activities discover
an injured or dead marine mammal, ODOT would be required to report the
incident to the NMFS Office of Protected Resources (OPR) at
<a href="/cdn-cgi/l/email-protection#461614680f1216680b29282f3229342f282114233629343235062829272768212930"><span class="__cf_email__" data-cfemail="ebbbb9c5a2bfbbc5a68485829f849982858cb98e9b84999f98ab85848a8ac58c849d">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#7a332e2a542a150e161519113a14151b1b541d150c"><span class="__cf_email__" data-cfemail="baf3eeea94ead5ced6d5d9d1fad4d5dbdb94ddd5cc">[email protected]</span></a>. ODOT would
also be required to report the incidental to the NOAA West Coast
Regional Stranding Coordinator as soon as feasible (1-866-767-6114;
more information found on NMFS' website: <a href="https://www.fisheries.noaa.gov/west-coast/marine-mammal-protection/west-coast-marine-mammal-stranding-network">https://www.fisheries.noaa.gov/west-coast/marine-mammal-protection/west-coast-marine-mammal-stranding-network</a>). If the death or injury were clearly
caused by the specified activity, ODOT would immediately cease the
specified activities until NMFS is able to review the circumstances of
the incident and determine what, if any, additional measures are
appropriate to ensure compliance with the IHA. ODOT would not resume
their activities until notified by NMFS. The report would include the
following information:
<bullet> Description of the incident;
<bullet> Environmental conditions (e.g., Beaufort sea state,
visibility);
<bullet> Description of all marine mammal observations in the 24
hours preceding the incident;
<bullet> Photographs or video footage of the animal(s) (if
equipment is available).
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive; and
<bullet> General circumstances under which the animal was
discovered.
Additionally, ODOT would be required to provide situational
reporting in the event that ODOT observes any entangled marine mammals,
they must report the sighting to the Entanglement Reporting Hotline (1-
877-SOS-WHAL (1-877-767-9425)) and the United States Coast Guard (VHF
Channel 16). Lastly, if ODOT observes any derelict gear, they must
report this to the Derelict Gear Hotline (1-855-542-3935).
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as
[[Page 34460]]
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
of the species listed in table 3, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Pile driving activities associated with ODOT's proposed
construction project have the potential to disturb or displace marine
mammals. Specifically, the project activities may result in take, in
the form of Level B harassment only, from underwater sounds generated
from vibratory pile driving and removal. Potential takes could occur if
individuals are present in the ensonified zone when these activities
are underway.
The takes by Level B harassment would be due to potential
behavioral disturbance. No serious injury or mortality would be
expected, even in the absence of required mitigation measures, given
the nature of the activities. The potential for harassment would be
further minimized through the construction method and the
implementation of the planned mitigation measures (see the Proposed
Mitigation section). Any potential for take by Level A harassment is
also not expected, given the nature of the activities and the small
distance to the Level A harassment threshold. The potential for this is
further reduced through the required mitigation measures proposed.
Given the small harassment zone estimated for vibratory pile driving
and the proximity of this zone to the construction barge, an animal
would have to remain within the area estimated to be ensonified above
the Level A harassment threshold for multiple hours. This is highly
unlikely given marine mammal movement in the area as well as the use of
observers stationed around the construction site.
Behavioral responses of marine mammals to pile driving in Yaquina
Bay are expected to be mild, short term, and temporary. Marine mammals
within the Level B harassment zones may not show any visual cues they
are disturbed by activities or they could become alert, avoid the area,
leave the area, or display other mild responses that are not
observable, such as changes in vocalization patterns. Given vibratory
pile driving would occur for only a portion of the project's duration,
any harassment that may occur would be expected to be temporary.
Additionally, many of the species present in region would only be
present temporarily based on seasonal patterns or during active transit
between other habitats. Pinnipeds in the area would have the ability to
haul-out to avoid the activities and no in-air harassment is
anticipated from the construction activities planned (refer back to
table 5). These temporarily present species would then be exposed to
even smaller periods of noise-generating activity, further decreasing
the impacts.
Any impacts on marine mammal prey that would occur during ODOT's
proposed activities would have, at most, short-term effects on foraging
of individual marine mammals, and likely no effect on the populations
of marine mammals as a whole. Indirect effects on marine mammal prey
during the construction are expected to be minor, and these effects are
unlikely to cause substantial effects on marine mammals at the
individual level, with no expected effect on annual rates of
recruitment or survival.
For all species and stocks, take would occur within a limited,
confined area of the stock's range, and there are no known BIAs near
the project area during the period of time vibratory pile driving is
planned to occur that would be impacted by ODOT's proposed activities.
While harbor seals and California sea lions are the species most likely
to occur within the immediate project area, the nearest haul outs are
located outside of the ensonified areas. There are a few known haul-out
sites for these two species near the project area, including to the
northeast (Bay Front haul-outs) and south (Finger Jetty haul-out), the
closest being 495 m (1,624 ft) from the project area (i.e., Finger
Jetty). The next closest haul-out site is 920 m (3,018.37 ft). There
are no other haul outs in the immediate project vicinity.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less the stocks' annual rates of
recruitment or survival. In combination, we believe that these factors,
as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities would have only minor, short-term effects on individuals.
The specified activities are not expected to impact rates of
recruitment or survival and would not be expected to result in
population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or proposed
to be authorized;
<bullet> No take by Level A harassment was requested, is expected,
or is proposed for authorization;
<bullet> For all species and stocks, Yaquina Bay is a very small
and peripheral part of their range;
<bullet> The intensity of anticipated takes by Level B harassment
is relatively low for all stocks. Level B harassment would be primarily
in the form of behavioral disturbance, resulting in avoidance of the
project areas around where vibratory pile driving is occurring;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
<bullet> The project area does not overlap any areas of known
important habitat (i.e., BIA) for marine mammals during the period
where they would be present (i.e., gray whales);
<bullet> The ensonified areas are very small relative to the
overall habitat ranges of all species and stocks; and
<bullet> There is a lack of anticipated significant or long-term
negative effects to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under section 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the
[[Page 34461]]
predicted number of individuals to be taken is less than one-third of
the species or stock abundance, the take is considered to be of small
numbers. Additionally, other qualitative factors may be considered in
the analysis, such as the temporal or spatial scale of the activities.
NMFS is proposing to authorize incidental take by Level B
harassment only of five species of marine mammals. No mortality or
serious injury has been requested, nor is it anticipated to occur from
the activities described herein. The maximum number of instances of
takes by Level B harassment proposed, relative to the best available
population abundance, is less than one-third for all species and stocks
potentially impacted (see table 11).
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals proposed for authorization, NMFS
preliminarily finds that small numbers of marine mammals would be taken
relative to the population size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
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
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency insure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of IHAs, NMFS consults
internally whenever we propose to authorize take for endangered or
threatened species.
No incidental take of ESA-listed 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 Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to ODOT's for conducting vibratory pile driving activities
at Yaquina Bay in Newport, Oregon from November 1, 2025, through
February 15, 2026, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated. A draft of the
proposed IHA can be found at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for ODOT's proposed
construction activities in Yaquina Bay. We also request comment on the
potential renewal of this proposed IHA as described in the paragraph
below. Please include with your comments any supporting data or
literature citations to help inform decisions on the request for this
IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned, or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
<bullet> 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: July 18, 2025.
Shannon Bettridge,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2025-13792 Filed 7-21-25; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on July 22, 2025.
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