Notice2023-19310
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Columbia East Lateral XPRESS Project
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 7, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from TC Energy Columbia Gulf Transmission, LLC for authorization to take marine mammals incidental to the East Lateral XPRESS Project in Barataria Bay, Louisiana. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 172 (Thursday, September 7, 2023)</title>
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[Federal Register Volume 88, Number 172 (Thursday, September 7, 2023)]
[Notices]
[Pages 61530-61548]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-19310]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD182]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Columbia East Lateral XPRESS
Project
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 TC Energy Columbia Gulf
Transmission, LLC for authorization to take marine mammals incidental
to the East Lateral XPRESS Project in Barataria Bay, Louisiana.
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, one-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than October
10, 2023.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#2b627f7b05785f4e5d4e457f5e48404e596b45444a4a054c445d"><span class="__cf_email__" data-cfemail="703924205e23041506151e2405131b1502301e1f11115e171f06">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas</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.
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-oil-and-gas">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas</a>. In case
of problems accessing these documents, please call the contact listed
below.
FOR FURTHER INFORMATION CONTACT: Steven Tucker, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least
[[Page 61531]]
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and requirements pertaining to the
mitigation, monitoring and reporting of the takings are set forth. The
definitions of all applicable MMPA statutory terms cited above are
included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review. We
will review all comments submitted in response to this notice prior to
concluding our NEPA process or making a final decision on the IHA
request.
Summary of Request
On March 3, 2023, NMFS received a request from TC Energy/Columbia
Gulf Transmission, LLC (Columbia Gulf) for an IHA to take marine
mammals incidental to construction activities that include pile driving
to install: (1) a point of delivery metering station (or, POD), and (2)
a tie-in facility (or, TIF) in Barataria Bay. The project is intended
to provide feed fuel for on-shore Liquefied Natural Gas (LNG)
compressor stations. The application was deemed adequate and complete
on June 5, 2023. Columbia Gulf's request is for take of bottlenose
dolphin (Tursiops truncatus, Barataria Bay Estuarine System stock or,
BBES) by Level B harassment only. Neither Columbia Gulf nor NMFS
expects serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
Columbia Gulf Transmission, LLC, a wholly-owned subsidiary of TC
Energy Corporation, proposes to construct two new compressor stations,
a new meter station, approximately 8 miles (13 kilometers) of new 30-
inch diameter natural gas pipeline lateral, two new mainline valves, a
tie-in facility, launcher and receiver facilities, and other auxiliary
appurtenant facilities all located in St. Mary, Lafourche, Jefferson,
and Plaquemines parishes, Louisiana (collectively referred to as
``Project''). A summary of all construction activities necessary to
complete the all elements of the project are shown in Table 1.
Table 1--All Elements of the Project. Bolded Elements Include In-Water Activities That May Result in the Take of
Marine Mammals
----------------------------------------------------------------------------------------------------------------
Pipeline milepost
Facility Parish location Description
----------------------------------------------------------------------------------------------------------------
Pipeline Facilities
----------------------------------------------------------------------------------------------------------------
30-inch Pipeline Lateral......... Jefferson.......... 0.00-2.47 Install approximately 13.1
kilometers (8.14) miles of new 30-
inch-diameter pipeline lateral.
Plaquemines........ 2.47-8.14 ..................................
----------------------------------------------------------------------------------------------------------------
Aboveground Facilities
----------------------------------------------------------------------------------------------------------------
Centerville Compressor Station... St. Mary........... \a\ 66.50, \b\ Construct a new gas-fired
66.70, \c\ 67.00 compressor station with a 23,470
hp compressor unit, which will
interconnect with Columbia Gulf's
existing EL-100, EL-200, and EL-
300 pipelines.
Golden Meadow Compressor Station. Lafourche.......... \c\ 149.50 Construct a new gas-fired
compressor station with a 23,470
hp compressor unit, which will
interconnect with Columbia Gulf's
existing EL-300 pipeline.
Point of Delivery Meter Station.. Plaquemines........ 8.14 Construct one point of delivery
meter station at the terminus of
the new 30-inch pipeline lateral
on an existing platform shared
with Venture Global Gator
Express, LLC. A 30-inch pig
receiver will also be installed
at the POD Meter Station.
Tie-in Facility.................. Jefferson.......... 0.00 Install a new tie-in facility
situated on a new platform at the
intersection of the new 30-inch
pipeline and Columbia Gulf's
existing EL-300 pipeline. A 30-
inch pig launcher will also be
Installed at the Tie-in Facility.
Valves and Other Ancillary Jefferson.......... 0.00, \c\ 1.71 Install one new 30-inch mainline
Facilities. valve assembly on the new 30-inch
pipeline lateral and one new 24-
inch mainline valve assembly
Columbia Gulf's existing EL-300
pipeline. Both mainline valve
assemblies will be situated on
the new Tie-in Facility platform.
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\a\ Milepost is associated with Columbia Gulf's existing EL-100 pipeline.
\b\ Milepost is associated with Columbia Gulf's existing EL-200 pipeline.
\c\ Milepost is associated with Columbia Gulf's existing EL-300 pipeline.
The work necessary to complete construction of the project would
temporarily impact 2.79 acres, permanently alter .02 acres and include
in-water activity that may result in take of marine mammals in
Barataria Bay. Specifically, in order to provide fuel supply services
to onshore LNG compressor stations, Columbia Gulf proposes pile driving
to construct a new Point of Delivery Meter Station on an existing
platform and a new Tie-in
[[Page 61532]]
Facility at the terminus a new 30-inch lateral pipeline. Project
activities include installation, by impact hammer, of 20 18-inch
concrete piles and 104 36-inch spun cast piles. The new POD Meter
Station will include the installation of three 16-inch meter runs and
related facilities. The new POD Meter Station will be constructed at
the site of an existing platform, and construction will require the
installation of four new 18-inch square concrete piles to protect a 30-
inch- diameter riser. Pipelines will be installed by jetting and
dredging with displaced sediment precipitating back to the substrate or
being side-cast adjacent to the trench, respectively.
The new Tie-in Facility will be situated on a new 180 foot (55
meter) long by 80 foot (24.3 meter) wide platform supported by 104 36-
inch-diameter spun cast and 4 18-inch-diameter concrete piles. Two 24-
inch-diameter and one 30-inch-diameter risers will be protected by 12
a8-inch diameter concrete piles. The Tie-in Facility would include a
boat landing measuring 10 foot (3 meter) long by 10 foot (3 meter)
wide, that will be used for maintenance and servicing of the platform.
These activities would be supported by eight vessels using existing
public barge channels and waterways during an estimated 16 barge trips
per week. Because vessels will be in transit, exposure to ship noise
will be temporary, relatively brief and will occur in a predictable
manner, producing sound at a relatively low level and consistent with
use of the waterway and other activity in the area. In order to reduce
the number barge transits during construction, Columbia Gulf intends to
station one or more barges onsite for hoteling of personnel.
Dates and Duration
Columbia Gulf proposes to start construction in January, 2024 in
order to meet a planned in-service date of April, 2025. Pile driving
within Barataria Bay is anticipated to occur within a 3 month period
from January, 2025 to March, 2025. Pile driving activity will be
intermittent, conducted in accordance with project phasing
requirements, and as such will not be continuous throughout the 3-month
period. Pile driving activities would take place from 7 a.m. to 7 p.m.
(adjusted as appropriate to conduct work during daylight hours), and
could occur on any day of the week for about 25 days (five piles per
day).
Specific Geographic Region
Barataria Bay is a shallow estuarine system, and is categorized as
an open bay habitat with a mean depth of approximately 2.0 meters (U.S.
Environmental Protection Agency, 1999; Conner and Day, 1987). Archival
data collected at NOAA's St. Mary's Point station indicate a mean tidal
range of 0.97 feet, with Mean High-High Water reference elevation of
.47' and Mean Low-Low Water reference elevation of -2.32. The bay has
two fronting barrier islands (Grand Isle and Grand Terre) that separate
it from the rest of the Gulf of Mexico and that also inhibit underwater
sound transmission from portions of the Bay to the coastal waters of
the Gulf of Mexico.
BILLING CODE 3510-22-P
[[Page 61533]]
[GRAPHIC] [TIFF OMITTED] TN07SE23.012
BILLING CODE 3510-22-C
Barataria Bay is bordered by tidal salt marshes and is connected to
a series of passes (i.e., Caminada Pass, Barataria Pass, Pass Abel, and
Quatre Bayou Pass) which, in turn, provide hydrologic connection to the
waters of the Gulf of Mexico (NMFS, 2023a; Conner and Day, 1987). To
the east, Barataria Bay is bounded by levees surrounding the
Mississippi River and to the west it is bordered by Bayou Lafourche
(Birdsong, 2004). The waters of Barataria Bay are turbid with lower
salinity level (including the presence of freshwater lakes) in northern
reaches. Higher salinity levels prevail in the southern portion of the
bay due to tidally influenced exchange with Gulf coastal waters (NMFS,
2023a). As a result, measured salinity concentrations in
[[Page 61534]]
Barataria Bay can vary ranging from 6 to 22 parts per trillion,
depending on the sampling location.
Detailed Description of the Specified Activity
Columbia Gulf proposes to construct a POD Meter Station on an
existing platform along with the new receiver at the terminus of a new
30-inch pipeline lateral within Barataria Bay. The new POD Meter
Station requires installation of three 16-inch meter runs and related
facilities. The new POD Meter Station is proposed for construction on
an existing platform, and requires the installation of four 18-inch
square concrete piles in order to protect a 30-inch-diameter riser.
In addition to shore side construction and installation of the POD
meter station, Columbia Gulf proposes to construct a new Tie-in
Facility at the intersection of the new 30-inch pipeline lateral and
Columbia Gulf's existing EL-300 pipeline. With the exception of a
portion of two new 24-inch-diameter risers and one new 30-inch-diameter
riser which will be underwater, the Tie-in Facility will be constructed
on a new 180 foot (55 meter) long by 80 foot (24.3 meter) wide platform
supported by 104 36-inch-diameter spun cast and 4 18-inch-diameter
concrete piles. Twelve 18-inch-diameter concrete piles will be
installed to protect the 2 24-inch-diameter and 1 30-inch-diameter
risers. The new platform will also be equipped with a boat landing,
which will measure 10 feet (3 meters) long by 10 feet (3 meters) wide
and will enable maintenance activities during operation of the Project.
Of the activities described in the application, noise from pile-
driving is the only activity expected to result in level B harassment
of bottlenose dolphins, and the implications of pile driving are
discussed in greater detail below. The Piles and method of installation
are presented in Table 2, below.
TABLE 2--Proposed Pile Driving Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Proposed pile Proxy pile for Impact strikes Strikes per Days of
Location piles diameter/type calculations per pile Piles per day day installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tie-in Facility................. 104 36'' Spun Cast 36'' Concrete 4,800 5 24,000 24
Concrete Piles. (round, hollow).
Tie-in Facility................. 16 18'' Concrete
(round).
Point of Delivery Platform...... 4 18'' Concrete 1
(square).
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Total....................... 120 25
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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 Barataria Bay Estuarine Stock (BBES)
of bottlenose dolphins. NMFS fully considered all of this information,
including relevant citations which may be included here, and we refer
the reader to these materials instead of reprinting the information.
Additional information regarding population estimates and potential
threats for the Barataria Bay Estuarine System stock of bottlenose
dolphins, can 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 information about this species in
general (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>).
Take of BBES bottlenose dolphins may occur incidental to the
specified activities described in the request for authorization.
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 is provided in Table 3. 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 from anthropogenic sources are
included here as gross indicators of the status of the species or
stocks and other threats.
The BBES abundance estimate presented in this document represents
the estimated total number of individuals within study and survey areas
in Barataria Bay. BBES are one of several estuarine stocks fringing the
northern Gulf of Mexico, and Barataria Bay is considered a Biologically
Important Area year-round for the Small and Resident Population. In
addition to Barataria Bay itself, individual BBES dolphins may be found
in Caminada Bay, Bay Coquette, and Gulf coastal waters extending 1
kilometer (km) from the shoreline (NMFS, 2023a).
The BBES stock was first designated in 1995 and is regarded as
distinct from populations in adjacent Gulf coastal waters based on
genetics, reproductive seasonality and direct observations. BBES
bottlenose dolphins are present throughout Bay year-round including in
the vicinity of the proposed construction site. Accordingly, when
estimating take and weighing potential impacts, BBES dolphin abundance,
density and distribution is presumed to be consistent throughout the
construction period. No additional assumptions or qualitative
adjustments were made based on seasonality. The values presented in
Table 2 are the most recent available at the time of publication
(including the draft 2022 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>.
[[Page 61535]]
Table 3--Marine Mammals Likely Impacted by the Specified Activities
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Stock
abundance
(CV, Nmin,
Common name Scientific name Stock ESA/MMPA status; most recent PBR Annual M/SI
strategic (Y/N) \2\ abundance \4\
survey) \3\
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Family Delphinidae
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Bottlenose Dolphin.................. Tursiops truncatus..... Barataria Bay Estuarine Y--Strategic.......... 2,071 18 160
Stock.
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\1\ 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 (2022).
\2\ 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.
\3\ NMFS marine mammal stock assessment reports online at: <a href="http://www.nmfs.noaa.gov/pr/sars/">www.nmfs.noaa.gov/pr/sars/</a>. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A
CV associated with estimated mortality due to commercial fisheries is presented in some cases.
As described above, animals from the BBES stock of bottlenose
dolphins temporarily and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While other marine
mammal species may occur in offshore waters of the Gulf of Mexico, the
characteristics of Barataria Bay make transits or sustained presence in
the area affected by the specified activity exceedingly unlikely and as
a result take is not expected to occur. Given take of other marine
mammal species is not expected, they are not discussed further.
The BBES stock has been affected by three declared unusual
mortality events, all of which are now closed. The first spanned
January through May of 1990 (in which 344 individuals became stranded),
the second from March 2010 to July 2014 (which included stranding
before, during, and after the Deepwater Horizon (DWH) oil spill), and
the third from February to November of 2019 and was found to be a
result of freshwater discharge from rivers (NMFS, 2023a).
Research conducted after the DWH oil spill found that the BBES
dolphins suffered a wide range of effects, including impaired
reproduction, respiratory illness, other diseases, and death. These and
other physiological and environmental challenges that followed the
spill impacted individual animals' ability to thrive and diminished the
health of the stock. In Barataria Bay alone, it is estimated that 45
percent of the common bottlenose dolphin population was lost following
the spill (Schwacke et al., 2021).
NMFS regards BBES dolphins to be a strategic stock. Insufficient
data exists to assess population trends for the stock. However, impacts
examined in the course of past Unusual Mortality Events, including
impacts from the DWH oil spill and changes in habitat characteristics,
coupled with an estimated PBR rate greater than 10 percent support the
Service's finding that the stock is strategic.
LeBreque et al. (2015) identified a small and resident population
Biologically Important Area for bottlenose dolphins in the Caminada Bay
and Southwest Barataria Bay area, indicating that the range of this
small population is limited to this area.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 4.
Table 4--Marine Mammal Hearing Groups (Nmfs, 2018)
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans.............. 275 Hz to 160 kHz.
(true porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
[[Page 61536]]
The pinniped hearing group was modified from Southall et al. (2007)
on the basis of data indicating that phocid species have consistently
demonstrated an extended frequency range of hearing compared to
otariids, especially in the higher frequency range (Hemil[auml] et al.,
2006; Kastelein et al., 2009; Reichmuth et al., 2013). This division
between phocid and otariid pinnipeds is now reflected in the updated
hearing groups proposed in Southall et al. (2019).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
presents the number of individual animals 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 activity
are expected to potentially occur from impact pile driving. The effects
of underwater noise from Columbia Gulf's activities have the potential
to result in Level B harassment of marine mammals in the action area.
These activities are not expected to cause serious injury or mortality,
and no take by Level A harassment is proposed.
Background on Sound
This section contains a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used relevant to
the specified activity and to a discussion of the potential effects of
the specified activity on marine mammals found later in this document.
For general information on sound and its interaction with the marine
environment, please see, Erbe and Thomas (2022); Au and Hastings
(2008); Richardson et al. (1995); Urick (1983); as well as the
Discovery of Sound in the Sea (DOSITS) website at <a href="https://dosits.org/">https://dosits.org/</a>.
Sound is a vibration that travels as an acoustic wave through a
medium such as a gas, liquid or solid. Sound waves alternately compress
and decompress the medium as the wave travels. In water, sound waves
radiate in a manner similar to ripples on the surface of a pond and may
be either directed in a beam (narrow beam or directional sources) or
sound may radiate in all directions (omnidirectional sources), as is
the case for sound produced by the pile driving activity considered
here. The compressions and decompressions associated with sound waves
are detected as changes in pressure by marine mammals and human-made
sound receptors such as hydrophones.
Sound travels more efficiently in water than almost any other form
of energy, making the use of sound as a primary sensory modality ideal
for inhabitants of the aquatic environment. In seawater, sound travels
at roughly 1,500 meters per second (m/s). In air, sound waves travel
much more slowly at about 340 m/s. However, the speed of sound in water
can vary by a small amount based on characteristics of the transmission
medium such as temperature and salinity.
The basic characteristics of a sound wave are frequency,
wavelength, velocity, and amplitude. Frequency is the number of
pressure waves that pass by a reference point per unit of time and is
measured in hertz (Hz) or cycles per second. Wavelength is the distance
between two peaks or corresponding points of a sound wave (length of
one cycle). Higher frequency sounds have shorter wavelengths than lower
frequency sounds, and typically attenuate (decrease) more rapidly with
distance, except in certain cases in shallower water. The amplitude of
a sound pressure wave is related to the subjective ``loudness'' of a
sound and is typically expressed in decibels (dB), which are a relative
unit of measurement that is used to express the ratio of one value of a
power or pressure to another. A sound pressure level (SPL) in dB is
described as the ratio between a measured pressure and a reference
pressure, and is a logarithmic unit that accounts for large variations
in amplitude; therefore, a relatively small change in dB corresponds to
large changes in sound pressure. For example, a 10-dB increase is a
ten-fold increase in acoustic power. A 20-dB increase is then a 100-
fold increase in power and a 30-dB increase is a 1000-fold increase in
power. However, a ten-fold increase in acoustic power does not mean
that the sound is perceived as being 10 times louder. The dB is a
relative unit comparing two pressures; therefore, a reference pressure
must always be indicated. For underwater sound, this is 1 microPascal
([mu]Pa). For in-air sound, the reference pressure is 20 microPascal
([mu]Pa). The amplitude of a sound can be presented in various ways;
however, NMFS typically considers three metrics: sound exposure level
(SEL), root-mean-square (RMS) SPL, and peak SPL (defined below). The
source level represents the SPL referenced at a standard distance from
the source (Richardson et al., 1995; American National Standards
Institute (ANSI), 2013)(typically 1 m) (Richardson et al., 1995;
American National Standards Institute (ANSI), 2013), while the received
level is the SPL at the receiver's position. For pile driving
activities, the SPL is typically referenced at 10 m.
SEL (represented as dB referenced to 1 micropascal squared second
(re 1 [mu]Pa\2\-s)) represents the total energy in a stated frequency
band over a stated time interval or event, and considers both intensity
and duration of exposure. The per-pulse SEL (e.g., single strike or
single shot SEL) is calculated over the time window containing the
entire pulse (i.e., 100 percent of the acoustic energy). SEL can also
be a cumulative metric; it can be accumulated over a single pulse (for
pile driving this is the same as single-strike SEL, above;
SEL<INF>ss</INF>), or calculated over periods containing multiple
pulses (SEL<INF>cum</INF>). Cumulative SEL (SEL<INF>cum</INF>)
represents the total energy accumulated by a receiver over a defined
time window or during an event. The SEL metric is useful because it
allows sound exposures of different durations to be related to one
another in terms of total acoustic energy. The duration of a sound
event and the number of pulses, however, should be specified as there
is no accepted standard duration over which the summation of energy is
measured.
RMS SPL is equal to ten times the logarithm (base 10) of the ratio
of the mean-square sound pressure to the specified reference value, and
given in units of dB (International Organization for Standardization
(ISO), 2017). RMS is calculated by squaring all of the sound
amplitudes, averaging the squares, and then taking the square root of
the average (Urick, 1983). RMS accounts for both positive and negative
values; squaring the pressures makes all values positive so that they
may be accounted for in the summation of pressure levels (Hastings and
Popper, 2005). This measurement is often used in the context of
discussing behavioral effects, in part because behavioral effects,
which often result from auditory cues, may be better expressed through
[[Page 61537]]
averaged units than by peak SPL. For impulsive sounds, RMS is
calculated by the portion of the waveform containing 90 percent of the
sound energy from the impulsive event (Madsen, 2005).
Peak SPL (also referred to as zero-to-peak sound pressure or 0-pk)
is the maximum instantaneous sound pressure measurable in the water,
which can arise from a positive or negative sound pressure, during a
specified time, for a specific frequency range at a specified distance
from the source, and is represented in the same units as the RMS sound
pressure (ISO, 2017). Along with SEL, this metric is used in evaluating
the potential for permanent threshold shift (PTS) and temporary
threshold shift (TTS) associated with impulsive sound sources.
Sounds are also characterized by their temporal components.
Continuous sounds are those whose sound pressure level remains above
that of the ambient or background sound with negligibly small
fluctuations in level (ANSI, 2005) while intermittent sounds are
defined as sounds with interrupted levels of low or no sound (National
Institute for Occupational Safety and Health (NIOSH), 1998). A key
distinction between continuous and intermittent sound sources is that
intermittent sounds have a more regular (predictable) pattern of bursts
of sounds and silent periods (i.e., duty cycle), which continuous
sounds do not.
Sounds may be either impulsive or non-impulsive (defined below).
The distinction between these two sound types is important because they
have differing potential to cause physical effects, particularly with
regard to noise-induced hearing loss (e.g., Ward, 1997 in Southall et
al., 2007). Please see NMFS (2018) and Southall et al. (2007; 2019) for
an in-depth discussion of these concepts.
Impulsive sound sources (e.g., sonic booms, seismic airgun shots,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; NIOSH, 1998; ANSI, 2005) and occur either as isolated
events or repeated in some succession. Impulsive sounds are all
characterized by a relatively rapid rise from ambient pressure to a
maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features. Impulsive
sounds are intermittent in nature. The duration of such sounds, as
received at a distance, can be greatly extended in a highly reverberant
environment.
Non-impulsive sounds can be tonal, narrowband, or broadband, brief
or prolonged, and may be either continuous or non-continuous (ANSI,
1995; NIOSH, 1998). Some of these non-impulsive sounds can be transient
signals of short duration but without the essential properties of
impulses (e.g., rapid rise time). Examples of non-impulsive sounds
include those produced by vessels, aircraft, machinery operations such
as drilling (including DTH systems) or dredging, vibratory pile
driving, and active sonar systems.
Even in the absence of sound from the specified activity, the
underwater environment is characterized by sounds from both natural and
anthropogenic sound sources. Ambient sound is defined as a composite of
naturally-occurring (i.e. non-anthropogenic) sound from many sources
both near and far (ANSI, 1995). Background sound is similar, but
includes all sounds, including anthropogenic sounds, minus the sound
produced by the proposed (NMFS, 2012; 2016). The sound level of a
region is defined by the total acoustical energy being generated by
known and unknown sources. These sources may include physical (e.g.,
wind and waves, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic (e.g., vessels, dredging, construction) sound. A number
of sources contribute to background and ambient sound, including wind
and waves, which are a main source of naturally occurring ambient sound
for frequencies between 200 Hz and 50 kilohertz (kHz) (Mitson, 1995).
In general, background and ambient sound levels tend to increase with
increasing wind speed and wave height. Precipitation can become an
important component of total sound at frequencies above 500 Hz, and
possibly down to 100 Hz during quiet times. Marine mammals can
contribute significantly to background and ambient sound levels, as can
some fish and snapping shrimp. The frequency band for biological
contributions is from approximately 12 Hz to over 100 kHz. Sources of
background sound related to human activity include transportation
(surface vessels), dredging and construction, oil and gas drilling and
production, geophysical surveys, sonar, and explosions. Vessel noise
typically dominates the total background sound for frequencies between
20 and 300 Hz. In general, the frequencies of many anthropogenic
sounds, particularly those produced by construction activities, are
below 1 kHz (Richardson et al., 1995). When sounds at frequencies
greater than 1 kHz are produced, they generally attenuate relatively
rapidly (Richardson et al., 1995), particularly above 20 kHz due to
propagation losses and absorption (Urick, 1983).
Transmission loss (TL) defines the degree to which underwater sound
has spread in space and lost energy after having moved through the
environment and reached a receiver. It is defined by the International
Standards Organization (ISO) as the reduction in a specified level
between two specified points that are within an underwater acoustic
field (ISO, 2017). Careful consideration of transmission loss and
appropriate propagation modeling is a crucial step in determining the
impacts of underwater sound, as it helps to define the ranges
(isopleths) to which impacts are expected and depends significantly on
local environmental parameters such as seabed type, water depth
(bathymetry), and the local speed of sound. Geometric spreading laws
are powerful tools which provide a simple means of estimating TL, based
on the shape of the sound wave front in the water column. For a sound
source that is equally loud in all directions and in deep water, the
sound field takes the form of a sphere, as the sound extends in every
direction uniformly. In this case, the intensity of the sound is spread
across the surface of the sphere, and thus we can relate intensity loss
to the square of the range (as area = 4*pi*r\2\). When expressing
logarithmically in dB as TL, we find that TL =
20*Log<INF>10</INF>(range), this situation is known as spherical
spreading. In shallow water, the sea surface and seafloor will bound
the shape of the sound, leading to a more cylindrical shape, as the top
and bottom of the sphere is truncated by the largely reflective
boundaries. This situation is termed cylindrical spreading, and is
given by TL = 10*Log<INF>10</INF>(range) (Urick, 1983). An intermediate
scenario may be defined by the equation TL =
15*Log<INF>10</INF>(range), and is referred to as practical spreading.
Though these geometric spreading laws do not capture many often
important details (scattering, absorption, etc.), they offer a
reasonable and simple approximation of how sound decreases in intensity
as it is transmitted. In the absence of measured data indicating the
level of transmission loss at a given site for a specific activity,
NMFS recommends practical spreading (i.e., 15*Log<INF>10</INF>(range))
to model acoustic propagation for construction activities in most
nearshore environments.
[[Page 61538]]
The sum of the various natural and anthropogenic sound sources at
any given location and time depends not only on the source levels, but
also on the propagation of sound through the environment. Sound
propagation is dependent on the spatially and temporally varying
properties of the water column and sea floor, and is frequency-
dependent. As a result of the dependence on a large number of varying
factors, background and ambient sound levels can be expected to vary
widely over both coarse and fine spatial and temporal scales. Sound
levels at a given frequency and location can vary by 10-20 dB from day
to day (Richardson et al., 1995). The result is that, depending on the
source type and its intensity, sound from the specified activity may be
a negligible addition to the local environment or could form a
distinctive signal that may affect marine mammals.
Description of Sound Sources for the Specified Activities
In-water construction activities expected to generate sound at
levels resulting in Level B harassment include impact pile
installation. Impact hammers operate by repeatedly dropping and/or
pushing a heavy piston onto a pile to drive the pile into the
substrate. Sound generated by impact hammers is impulsive,
characterized by rapid rise times and high peak levels, a potentially
injurious combination (Hastings and Popper, 2005).
The likely or possible impacts of the Columbia Gulf'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, visual
and other non-acoustic stressors would be limited, and any impacts to
marine mammals are expected to primarily be acoustic in nature.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving or drilling is the primary means by which
marine mammals may be harassed from the Columbia Gulf's specified
activity. In general, animals exposed to natural or anthropogenic sound
may experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007; 2019). Exposure to pile
driving has the potential to result in auditory threshold shifts and
behavioral reactions (e.g., avoidance, temporary cessation of foraging
and vocalizing, changes in dive behavior). Exposure to anthropogenic
noise can also lead to non-observable physiological responses, such an
increase in stress hormones. Additional noise in a marine mammal's
habitat can mask acoustic cues used by marine mammals to carry out
daily functions, such as communication and predator and prey detection.
The effects of pile driving on marine mammals is dependent on several
factors, including, but not limited to, sound type (e.g., impulsive vs.
non-impulsive), the species, age and sex class (e.g., adult male vs.
mom with calf), duration of exposure, the distance between the pile and
the animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2004; Southall et al., 2007).
Here we discuss physical auditory effects (threshold shifts) followed
by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS, 2018, there are numerous factors to
consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
frequency range of the exposed species relative to the signal's
frequency spectrum (i.e., how animal uses sound within the frequency
band of the signal; e.g., Kastelein et al. (2014)), and the overlap
between the animal and the source (e.g., spatial, temporal, and
spectral). When considering auditory effects for Columbia Gulf's
proposed activities, impact pile driving is treated as an impulsive
source.
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). PTS does not
generally affect more than a limited frequency range, and an animal
that has incurred PTS has incurred some level of hearing loss at the
relevant frequencies; typically animals with PTS 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 PTS onset (see Ward et al. (1958; 1959); Ward, 1960;
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson et
al., 2008). PTS levels for marine mammals are estimates, as with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al., 2008), there are no empirical data measuring PTS
in marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--A temporary, reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). Based on data from 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; Schlundt et al., 2000; Finneran et al., 2002). As described
in Finneran (2015), marine mammal studies have shown the amount of TTS
increases with SELcum in an accelerating fashion: at low exposures with
lower SELcum, the amount of TTS is typically small and the growth
curves have shallow slopes. At exposures with higher SELcum, the growth
curves become steeper and approach linear relationships with the noise
SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al.,
[[Page 61539]]
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). 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 at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a; 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, cumulative
SEL 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, 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, 2018).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS 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 PTS 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
PTS 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 PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Behavioral Harassment--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 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); avoidance of areas where sound sources are located.
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; Weilgart, 2007; Archer et al., 2010;
Southall et al., 2019). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). Please see
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,
[[Page 61540]]
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 showed pronounced behavioral
reactions, including avoidance of loud sound sources (Ridgway et al.,
1997; Finneran et al., 2003). Observed responses of wild marine mammals
to loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (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. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
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).
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 (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
(Eschrictius robustus) are known to change direction--deflecting from
customary migratory paths--in order to avoid noise from seismic surveys
(Malme et al., 1984). Avoidance may be short-term, with animals
returning to the area once the noise has ceased (e.g., Bowles et al.,
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey
et al., 2007). Longer-term displacement is possible, however, which may
lead to changes in abundance or distribution patterns of the affected
species in the affected region if habituation to the presence of the
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al.,
2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; 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
[[Page 61541]]
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 behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., 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). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2005), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar construction projects and given
the anticipated effectiveness of proposed mitigation measures.
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 environment
are being severely masked could also be impaired from maximizing their
performance fitness for 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).
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.
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
[[Page 61542]]
through other compensatory behaviors (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).
Marine mammals at or near the project site may be exposed to
anthropogenic noise which may lead to some habituation, but is also a
source of masking. Vocalization changes may result from a need to
compete with an increase in background noise and include increasing the
source level, modifying the frequency, increasing the call repetition
rate of vocalizations, or ceasing to vocalize in the presence of
increased noise (Hotchkin and Parks, 2013).
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources. Energy distribution of pile
driving covers a broad frequency spectrum, and sound from pile driving
would be within the audible range of marine mammals. While some
construction during Columbia Gulf's activities may mask some acoustic
signals that are relevant to the daily behavior of BBES dolphins if
they are in the vicinity of the project, the short-term duration and
limited areas affected make it very unlikely that reproductive success
or survival of individual animals would be affected.
Water quality--Temporary and localized reduction in water quality
will occur as a result of in-water construction activities. The
installation of piles and proposed dredging for pipeline installation
will disturb bottom sediments and will cause a temporary increase in
suspended sediment in the project area. In general, turbidity
associated with pile driving is localized to about a 25-ft (7.6m)
radius around the pile (Everitt et al. 1980). 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 from project-related 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 are expected to dissipate and return to background
levels. In general, turbidity within the water column can contribute to
reduced oxygen levels in the water and can 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 that may
be impacted by the proposed construction activities is relatively small
compared to the available marine mammal habitat in Barataria Bay.
In addition to sediment, due to the natural and human history of
Barataria bay, work that disturbs the substrate could encounter
residual, undetected petroleum material deposited as a result of
naturally occurring seeps or that resulted from past extraction
activities. The most likely location for encountering such material is
in at the coastline and within or proximate to the intertidal zone.
Columbia Gulf will take all appropriate precautions to prevent the
resuspension of contaminated media and will notify all appropriate
authorities if weathered oil is encountered during construction
activities
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, 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. 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 condition 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 4-6 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; Casper et al., 2017).
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation. 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
[[Page 61543]]
internal injury (Hastings and Popper, 2005).
The greatest potential impact to fishes during construction would
occur during impact pile driving. In-water construction activities
would only occur during daylight hours, allowing fish to forage and
transit the project area in the evening. In general, impacts on marine
mammal prey species are expected to be minor and temporary.
Potential Effects on Foraging Habitat--The proposed activities
would not result in permanent impacts to habitats used directly by
marine mammals. The total seafloor area affected by the project during
construction is estimated to be 2.79 acres, of which .02 acres would be
permanently altered. This alteration represents a small portion of the
foraging area available to marine mammals outside this project vicinity
and in broader Barataria Bay. Construction would have minimal impacts
on invertebrate species (principally shrimp), which have been
identified as target prey of BBES dolphins (Bowens-Stevens, 2021).
Barataria Bay is designated as essential fish habitat for several
species, some of which serve as prey for BBES dolphins. However, given
the short daily duration of sound associated with individual pile
driving and the relatively small areas being affected, pile driving
associated with the project is not likely to have a permanent adverse
effect on any fish habitat, or populations of fish species. Also, the
area impacted by the project is relatively small compared to the
available habitat just outside the project area. Therefore, impacts of
the project are not likely to have adverse effects on marine mammal
foraging habitat in the proposed project area.
In summary for this project, serious injuries to or mortality of
BBES dolphins are not anticipated as a result of shore side activities
or in-water construction for the project and neither, as described in
greater detail in the Estimated Take section, is PTS (Level A
harassment). However, behavioral impacts could occur due to the
increase in underwater noise resulting from pile driving activities.
Potential acoustic disturbance originating from the specified
activities considered here is expected to be of a relatively short
duration, likely in the form of avoidance of the area while activities
are being conducted. Pile driving is proposed to take place from 7 a.m.
to 7 p.m. (adjusted as appropriate to conduct work during daylight
hours), and may occur on any day of the week for approximately 25 days
of in-water work. Bottlenose dolphins are expected to avoid the project
area during pile driving activities, though dolphins could be present
when pile driving begins. Columbia Gulf proposes to implement
mitigation measures such as pre-clearance monitoring and adherence to a
soft-start protocol in order to mitigate against adverse impacts to
dolphins that may be in the area when work commences or is restarted.
Sufficient monitoring will be maintained in order to detect marine
mammals in the area and implement any necessary response including work
stoppage, should it become necessary.
The specified activity could cause localized impacts to dolphin
prey, but is otherwise unlikely to affect habitat. While some injury or
loss of prey animals may occur, fish are expected to avoid the project
area during pile driving activities and changes in abundance of prey
are not expected.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to sound emanated from pile driving activity.
Based on the nature of the activity and the anticipated effectiveness
of the mitigation measures including the utilization of Protected
Species Observers to monitor for marine mammals and implementation of
pre-clearance and soft start protocols discussed in detail below in the
Proposed Mitigation section, Level A harassment is neither anticipated
nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment for
example, permanent threshold shift (or PTS); (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
[[Page 61544]]
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 Temporary Threshold Shift (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 that would not otherwise occur.
Columbia Gulf's Request for Authorization includes actions known to
generate impulsive sound (impact pile driving) that may cause
incidental harassment, and therefore the RMS SPL threshold of 160 re 1
[mu]Pa is applicable.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). The
specified activity proposed by Columbia Gulf includes the use of an
impulsive source type and is proposed to occur in an area where BBES
bottlenose dolphins, a mid-frequency cetacean, are found.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, available at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (Received Level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1 Lpk,flat: 219 dB Cell 2 LE,LF,24h: 199 dB
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3 Lpk,flat: 230 dB Cell 4 LE,MF,24h: 198 dB
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5 Lpk,flat: 202 dB Cell 6 LE,HF,24h: 173 dB
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7 Lpk,flat: 218 dB Cell 8 LE,PW,24h: 201 dB
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9 Lpk,flat: 232 dB Cell 10 LE,OW,24h: 219 dB
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area that may be ensonified to
levels above the acoustic thresholds, including source levels and
transmission loss coefficient.
To calculate the ensonified area, Columbia Gulf used the NMFS User
Spreadsheet and accompanying 2018 guidance. Columbia Gulf located data
for impact installation of a 36 inch concrete pile (McGillvary, 2007),
measured at 50 meters, to serve as a suitable proxy source level for
the 104 36-inch spun-cast piles selected for the project (see Table 6).
The applicant then elected to apply the source levels for the 36-in
proxy pile to all piles being driven, including the 20 18-inch piles,
likely resulting in an overestimate of resulting noise from these
smaller piles.
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 * Log10 (R1/R2), where:
TL = Transmission loss in dB,
B = Transmission loss coefficient,
R1 = the distance of the modeled SPL from the driving pile, and
R2 = the distance from the driven pile of the initial measurement.
Absent site-specific acoustical monitoring with differing measured
transmission loss, a practical spreading value of 15 is used as the
transmission loss coefficient. Site-specific transmission loss data for
the project area in Barataria 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. There,
NMFS developed an optional User Spreadsheet and accompanying 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 the 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 Level A harassment. However, this optional
tool offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such as pile driving, the options User Spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur PTS. Inputs used in the option User Spresheet tool, and the
resulting estimated isopleths, are reported in Tables 6 and 7, below.
The applicant as applied a 15LogR propagation loss rate in the User
Spreadsheet, and included a 5 dB attenuation factor for proposed use of
a bubble curtain which is consistent with NMFS guidelines.
[[Page 61545]]
Table 6--Proxy Pile Characteristics (User Spreadsheet Input)
----------------------------------------------------------------------------------------------------------------
SLs
Pile type ------------------------------------------ Measured distance Source
dB Peak dB rms dB SEL
----------------------------------------------------------------------------------------------------------------
36'' concrete pile, Impact pile 186 174 160 50 meters......... MacGillivary,
driven (5 dB attenuated). 2007.
----------------------------------------------------------------------------------------------------------------
To calculate the harassment zones, Columbia Gulf identified a
representative location in the center of the Tie-in Facility and second
representative location in the center of the POD Meter Station and used
these locations to calculate the harassment zones for each site. Given
the close proximity of individual piles to one another, NMFS concurred
with this approach. Columbia Gulf then accessed the User Spreadsheet to
calculate the distance from each of the two representative pile driving
locations to the furthest extent of Level A and Level B thresholds for
mid-frequency cetaceans. In order to ensure conservative results, the
source level data for 36 inch piles was used as a proxy for all pile
driving activities, including installation of smaller diameter piles.
Table 7--Harassment Zone Isopleths Attributable To Proposed Pile Driving
------------------------------------------------------------------------
Distance from representative sound
source
---------------------------------------
Behavioral
Activity PTS: Level A disturbance: Level
harassment zone B harassment zone
(mid-frequency (all marine
cetaceans) mammals)
------------------------------------------------------------------------
Impact pile driving in Barataria 142.0 feet........ 1,407.0 feet.
Bay \a\.
------------------------------------------------------------------------
\a\ User Spreadsheet output based on installation by impact hammer of
(proxy) 36-inch-diameter concrete piles, and use of bubble curtains
(estimated 5 dB reduction, per consultations with NMFS) (MacGillivray
et al., 2007).
Based on the user spreadsheet outputs reflected in Table 5, the
Level B harassment zone would have a radius of approximately 1,407.0
feet (428.9 meters) from the source pile, or an approximate area of
0.58 square kilometers (km\2\). The Level A zone would have a
calculated radius of approximately 142.0 feet (43.2 meters), or an
approximate area of 63,347 square feet (0.006 km\2\). Columbia Gulf
plans to implement a 50 meter shutdown zone that extends coverage
beyond the 43.2 meter Level A harassment zone indicated by the User
Spreadsheet. As a result, given that detection of bottlenose dolphins
within this distance is expected to be successful, no Level A take is
anticipated to occur, or proposed to be authorized, as a result of
project activities.
Marine Mammal Occurrence
In order to estimate the distribution and density of BBES dolphins
that may occur in the area affected by the specified activity, we turn
to prior area-specific surveys and studies conducted in the Bay.
Density estimates for Columbia Gulf's proposal reference the
findings of the 2017 McDonald (et al.) study and an average of the
calculated densities for each habitat region defined within the study
area. Density estimates for bottlenose dolphins within Barataria Bay
were derived from estimates calculated through vessel-based capture-
mark-recapture photo-ID surveys conducted during ten survey sessions
from June 2010 to May 2014 (McDonald et.al., 2017). Because the surveys
were conducted during the DWH oil spill, the resulting density estimate
does not account for mortality following the spill.
The study was conducted from June 2010 to May 2014 and utilized
vessel-based capture-mark-recapture photo ID surveys. The study area
for these surveys included Barataria Bay and Pass, Bayou Rigaud,
Caminada Bay and Pass, Barataria Waterway, and Bay des Ilettes.
Densities varied in different areas within broader Barataria Bay, and
the study area was divided into three (East, West, and Island) habitat
regions to capture these observed density variations. Results were
parsed and densities were calculated for each habitat region. Project
activities may have some effect on both the East and West habitat
regions, with estimated densities of 0.601 individuals per km\2\ and
1.24 individuals per km\2\, respectively. Study results indicate
density of 11.4 individuals per km\2\ for the Island region. Given
uncertainties regarding fidelity to and transiting among habitat
regions, the average densities for each habitat region in the study
area are then averaged together to create an estimated density for the
project area. NMFS concurs with this approach. Inclusion of the higher
estimated density from the Island habitat region results in a
cumulative average higher than the estimated density for the East and
West habitat regions alone, and reflects a conservative approach. Based
on this calculation and using the best available information for
estimating density given the project type and location, the average
bottlenose dolphin density for the project is estimated to be 2.83
individuals per km\2\.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
[[Page 61546]]
Table 8--Level B Harassment Takes Requested and Percentage of Stock Potentially Affected
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percentage (%)
Level B Level B takes of stock
Pile driving location Species Estimated density harassment requested Stock abundance potentially
area (individuals) (individuals) affected by
Level B take
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tie-In Facility..................... Bottlenose Dolphin 2.83 0.58 km\2\ 40 2,071 1.93
individuals per km\2\.
POD Meter Station................... 2...................... 0.10..................
Project Totals.................. 42..................... --.................... 2.03
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Take estimates for pile driving activities were calculated
using the density estimate described above, averaging across the three
areas in Barataria Bay. The Level B harassment zone is calculated using
source level data for 36-inch concrete piles (including use of bubble
curtains) and assumes an even distribution of animals throughout the
affected area. Initial Level B take estimates for Tie-in Facility and
POD Meter Station pile driving activity were calculated using the area
of the Level B harassment zone (0.58 km\2\) multiplied by the
calculated density (2.83 individuals per km\2\). This results in a
daily take estimate of 1.64 individuals for pile driving at the Tie-in
Facility and the POD Meter Station. The daily Level B harassment
estimate (1.64 individuals) was then multiplied by the number of days
when pile driving will take place (24 days at the Tie-in Facility and 1
day at the POD Meter Station) to calculate the number of requested
takes for pile driving related to the Project. The estimated takes are
indicated in Table 8.
Level A harassment is not anticipated to occur and authorization of
Level A take is not requested. In-water construction activities will be
completed within one to two months (a total of 25 to 42 days) and are
not expected to result in serious injury or mortality to marine mammals
within Barataria Bay. Based on calculated threshold distances in Table
7 for mid-frequency cetaceans, an individual would need to remain
within 142.0 feet of the piles being driven throughout the entire day
of pile driving activities for cumulative exposure injury to occur.
Given the mobility of bottlenose dolphins and the expected behavior of
the species to avoid noise disturbance (i.e., pile driving), such a
scenario is extremely unlikely to occur.
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, impact on
operations.
Mitigation for Marine Mammals and Their Habitat
Columbia Gulf will retain and deploy qualified Protected Species
Observers to ensure that dolphins are not present within 1,407.0 feet
(428.8 meters) of the pile driving area when pile driving activities
begin. If dolphins are observed entering the area in which the injury
threshold will be exceeded (i.e., Level A, calculated to be 142.0 feet
[43.2 meters] and established at 50 meters), pile driving will cease
until they leave the area. All vessels engaged in construction and crew
transport will adhere to NMFS's Vessel Strike Avoidance Measures and to
related reporting requirements for mariners. Through the implementation
of these measures and those that follow, Columbia Gulf will ensure that
dolphins and other marine mammals are not present within an area where
Level A harassment could occur.
Columbia Gulf proposes the following additional mitigation
measures:
<bullet> Establishment and monitoring of Pre-clearance zones to
survey for presence of marine mammals prior to commencement/resumption
of work.
<bullet> Implementation of soft start protocols to ensure initial
sound stimulus is not at a harmful level.
<bullet> Adoption of a conservative 50 meter shutdown zone to
preclude Level A take.
<bullet> Positioning of Protected Species Observers authorized to
direct work stoppage if circumstances warrant.
<bullet> Deployment of a submerged bubble curtain to dampen sound
from impact driving.
<bullet> Work stoppage should any marine mammal take not permitted
by the IHA occur followed by reporting to NOAA Fisheries as soon as
practicable and within 24 hours.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact to BBES
bottlenose dolphins and their habitat.
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.
[[Page 61547]]
Effective reporting is critical both to compliance as well as ensuring
that the most value is obtained from the required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Below is a summary of the monitoring measures included in the
application and proposed for pile installation activities associated
with the Project (see the draft IHA for additional detail):
<bullet> At least one NOAA Fisheries-approved observers (i.e.,
Protected Species Observers [PSOs]) will be on duty and assigned to the
highest possible vantage point in order to maintain a 360-degree view
of the project area.
<bullet> A 1,407.0 feet (428.8 meters) pre-clearance zone for
marine mammals will be established using range finding equipment and
monitored by the PSOs.
<bullet> Observers will monitor the NOAA-approved 50 meter shutdown
zone during all pile installation activities.
<bullet> Observers will maintain a continuous watch while pile
driving activities are under way, using binoculars and/or naked eye
observations to continuously search for marine mammals.
<bullet> If marine mammals are observed in the Project area, the
sighting will be fully documented, including the following (among
others), when possible:
[cir] Bearing to animal relative to observer position;
[cir] Number of individuals observed;
[cir] Estimated location within the Project area;
[cir] Type of construction activity (i.e., impact pile driving);
and
<bullet> Behavioral state, possible reaction of the animal(s) to
the pile driving, and any behaviors of the animal/s while in the
Project area.Observers will make note of the state of Barataria Bay
using the Beaufort scale and collect and record weather conditions
during the course of marine mammal monitoring.
Proposed Reporting
Columbia Gulf would provide the NOAA Fisheries Service with a draft
comprehensive monitoring report within 90 days of the conclusion of
monitoring. This report would include the following (please see draft
IHA for additional detail):
<bullet> A summary of the Project activity (e.g., Project actions,
dates, times, durations, and locations)
<bullet> A summary of mitigation implementation
<bullet> Monitoring results and a summary that addresses the goals
of the monitoring plan, including (but not limited to):
[cir] Environmental conditions when observations were made (e.g.,
water conditions and weather);
[cir] Date and time of observations (initiation and termination);
[cir] Date, time, number, species, and any other relevant data
regarding marine mammals observed;
[cir] Description of the observed behaviors; and
[cir] Assessment of implementation and effectiveness of prescribed
mitigation and monitoring measures.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
The BBES stock of bottlenose dolphins is considered a strategic
stock because mortality attributable to human activity is thought to
exceed PBR. Potential effects of this project on BBES dolphins include
behavioral modification resulting from Level B harassment and temporary
avoidance of the construction area. As decribed above, no Level A
harassment is expected and no authorization of Level A take is not
proposed. Given the nature of the harassment, its temporary nature and
proposed mitigation, NMFS anticipates impacts from the specified
activity on individuals and the stock would be negligible.
The project site is within a designated Biologically Important Area
for Small and Resident Populations. The BBES stock is present within
the area year-round. All life activities may occur within the
designated BIA including the project area. The project area represents
a small portion of available habitat and the BIA, and adjacent areas of
open water within the embayment that would remain accessible to BBES
dolphins throughout the construction process. Proper implementation of
the mitigation measures described above support a finding that the
impacts of Level B harassment would be minimized and likely have
negligible effect on individual animals or the BBES population of
bottlenose dolphins.
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 BBES bottlenose
dolphins by reducing annual rates of recruitment or survival:
[[Page 61548]]
<bullet> No serious injury or mortality is anticipated or
authorized; and no impacts to reproductive success or survival of any
individual animals are expected.
<bullet> The required mitigation measures are expected to avoid any
Level A harassment and to reduce the number and severity of takes by
Level B harassment.
<bullet> Behavioral impacts and displacement that may occur in
response to pile driving, is expected to be limited in duration to
approximately 25 days concurrent with in-water construction activity.
<bullet> The specified activities do not impact any known important
habitat areas such as calving grounds or unique feeding areas, and
alternate habitat is readily available.
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 pile driving activity will have a
negligible impact on BBES bottlenose dolphins.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
Based on a conservative estimate of the number of takes that may
occur as a result of pile driving activities, less than two percent of
the BBES population would be subject to take via Level B harassment.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
No subsistence uses of BBES bottlenose dolphins are known to occur.
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 Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed under the
auspices of this authorization. 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 Columbia Gulf, LLC to conduct the specified pile
driving activity in Barataria Bay, Louisiana during the 1-year period
of authorization, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the specified
activity. 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 one year from
expiration of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: September 1, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-19310 Filed 9-6-23; 8:45 am]
BILLING CODE 3510-22-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.