Proposed Rule2021-14542
Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Point Mugu Sea Range Study Area
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
July 16, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the U.S. Navy (Navy) to take marine mammals incidental to training and testing activities conducted in the Point Mugu Sea Range (PMSR) Study Area. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue regulations and subsequent Letter of Authorization (LOA) to the Navy to incidentally take marine mammals during the specified activities. NMFS will consider public comments prior to issuing any final rule and making final decisions on the issuance of the requested LOA. Agency responses to public comments will be summarized in the notice of the final decision in the final rule. The Navy's activities qualify as military readiness activities pursuant to the MMPA, as amended by the National Defense Authorization Act for Fiscal Year 2004 (2004 NDAA).
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[Federal Register Volume 86, Number 134 (Friday, July 16, 2021)]
[Proposed Rules]
[Pages 37790-37852]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-14542]
[[Page 37789]]
Vol. 86
Friday,
No. 134
July 16, 2021
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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50 CFR Part 218
Taking and Importing Marine Mammals; Taking Marine Mammals Incidental
to the U.S. Navy Training and Testing Activities in the Point Mugu Sea
Range Study Area; Proposed Rule
Federal Register / Vol. 86 , No. 134 / Friday, July 16, 2021 /
Proposed Rules
[[Page 37790]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 218
[Docket No. 210701-0141]
RIN 0648-BK07
Taking and Importing Marine Mammals; Taking Marine Mammals
Incidental to the U.S. Navy Training and Testing Activities in the
Point Mugu Sea Range Study Area
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments and information.
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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) to take
marine mammals incidental to training and testing activities conducted
in the Point Mugu Sea Range (PMSR) Study Area. Pursuant to the Marine
Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue regulations and subsequent Letter of Authorization
(LOA) to the Navy to incidentally take marine mammals during the
specified activities. NMFS will consider public comments prior to
issuing any final rule and making final decisions on the issuance of
the requested LOA. Agency responses to public comments will be
summarized in the notice of the final decision in the final rule. The
Navy's activities qualify as military readiness activities pursuant to
the MMPA, as amended by the National Defense Authorization Act for
Fiscal Year 2004 (2004 NDAA).
DATES: Comments and information must be received no later than August
30, 2021.
ADDRESSES: Submit all electronic public comments via the Federal e-
Rulemaking Portal. Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a> and enter NOAA-
NMFS-2021-0064 in the Search box. Click on the ``Comment'' icon,
complete the required fields, and enter or attach your comments.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
<a href="http://www.regulations.gov">www.regulations.gov</a> without change. All personal identifying
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible. NMFS will accept anonymous comments (enter
``N/A'' in the required fields if you wish to remain anonymous).
Attachments to electronic comments will be accepted in Microsoft Word,
Excel, or Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT: Stephanie Egger, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <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>. In case of problems accessing these
documents, or for anyone who is unable to comment via electronic
submission, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, issued under the authority of the MMPA
(16 U.S.C. 1361 et seq.), would provide the framework for authorizing
the take of marine mammals incidental to the Navy's training and
testing activities (which qualify as military readiness activities)
from the use of at-surface and near-surface explosive detonations
throughout the PMSR Study Area, as well as launch events from San
Nicolas Island (SNI). The Study Area includes 36,000 square miles and
is located adjacent to Los Angeles, Ventura, Santa Barbara, and San
Luis Obispo Counties along the Pacific Coast of Southern California
(see Figure 1.1 of the application). The two primary components of the
PMSR are the Special Use Airspace (SUA) and the ocean Operating Areas
(PMSR-controlled sea space). The PMSR-controlled sea space parallels
the California coast for approximately 225 nautical miles (nmi) and
extends approximately 180 nmi seaward (see Figure 1-1 of the
application).
NMFS received an application from the Navy requesting seven-year
regulations and an authorization to incidentally take individuals of
multiple species of marine mammals (``Navy's rulemaking/LOA
application'' or ``Navy's application''). Take is anticipated to occur
by Level A and Level B harassment incidental to the Navy's training and
testing activities, with no serious injury or mortality expected or
proposed for authorization.
Background
The MMPA prohibits the take of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA direct the
Secretary of Commerce (as delegated to NMFS) to allow, upon request,
the incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review and the opportunity to submit
comments.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stocks and will not have an unmitigable adverse impact on the
availability of the species or stocks for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other means of effecting the least practicable adverse
impact on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in this rule as
``mitigation measures''). NMFS also must prescribe the requirements
pertaining to the monitoring and reporting of such takings. The MMPA
defines ``take'' to mean to harass, hunt, capture, or kill, or attempt
to harass, hunt, capture, or kill any marine mammal. The Preliminary
Analysis and Negligible Impact Determination section below discusses
the definition of ``negligible impact.''
The NDAA for Fiscal Year 2004 (2004 NDAA) (Pub. L. 108-136) amended
section 101(a)(5) of the MMPA to remove the ``small numbers'' and
``specified geographical region'' provisions indicated above and
amended the definition of ``harassment'' as applied to a ``military
readiness activity.'' The definition of harassment for military
readiness activities (section 3(18)(B) of the MMPA) is: (i) Any act
that injures or has the significant potential to injure a marine mammal
or marine mammal stock in the wild (Level A Harassment); or (ii) Any
act that disturbs or is likely to disturb a marine mammal or marine
mammal stock in the wild by causing disruption of natural behavioral
patterns, including, but not limited to, migration, surfacing, nursing,
breeding, feeding, or sheltering, to a point where such behavioral
patterns are abandoned or significantly altered (Level B harassment).
In addition, the 2004 NDAA amended the MMPA as it relates to military
readiness activities
[[Page 37791]]
such that the least practicable adverse impact analysis shall include
consideration of personnel safety, practicality of implementation, and
impact on the effectiveness of the military readiness activity.
More recently, section 316 of the NDAA for Fiscal Year 2019 (2019
NDAA) (Pub. L. 115-232), signed on August 13, 2018, amended the MMPA to
allow incidental take rules for military readiness activities under
section 101(a)(5)(A) to be issued for up to seven years. Prior to this
amendment, all incidental take rules under section 101(a)(5)(A) were
limited to five years.
Summary and Background of Request
On March 9, 2020, NMFS received an application from the Navy for
authorization to take marine mammals by Level A and Level B harassment
incidental to training and testing activities (categorized as military
readiness activities) from (1) the use of at-surface or near-surface
explosive detonations in the PMSR Study Area, as well as (2) launch
events from SNI, over a seven-year period beginning October 2021
through October 2028. We received a revised application on August 28,
2020, which provided minor revisions to the mitigation and monitoring
sections, and upon which the Navy's rulemaking/LOA application was
found to be adequate and complete. On September 4, 2020, we published a
notice of receipt (NOR) of application in the Federal Register (85 FR
55257), requesting comments and information related to the Navy's
request for 30 days. We reviewed and considered all comments and
information received on the NOR in development of this proposed rule.
The following types of training and testing, which are classified
as military readiness activities pursuant to the MMPA, as amended by
the 2004 NDAA, will be covered under the regulations and LOA: Air
warfare (air-to-air, surface-to-air), electronic warfare (directed
energy--lasers and high-powered microwave systems), and surface warfare
(surface-to-surface, air-to-surface, and subsurface-to surface). The
proposed activities will not include any sonar, pile driving/removal,
or use of air guns.
The Navy's mission is to organize, train, equip, and maintain
combat-ready naval forces capable of winning wars, deterring
aggression, and maintaining freedom of the seas. This mission is
mandated by Federal law (10 U.S.C. 8062), which requires the readiness
of the naval forces of the United States. The Navy executes this
responsibility by training and testing at sea, often in designated
operating areas (OPAREA) and testing and training ranges. The Navy must
be able to access and utilize these areas and associated sea space and
air space in order to develop and maintain skills for conducting naval
operations. The Navy's testing activities ensure naval forces are
equipped with well-maintained systems that take advantage of the latest
technological advances. The Navy's research and acquisition community
conducts military readiness activities that involve testing. The Navy
tests ships, aircraft, weapons, combat systems, sensors, and related
equipment, and conducts scientific research activities to achieve and
maintain military readiness.
The Navy has been conducting testing and training activities in the
PMSR Study Area since the PMSR was established in 1946. The tempo and
types of training and testing activities fluctuate because of the
introduction of new technologies, the evolving nature of international
events, advances in warfighting doctrine and procedures, and changes in
force structure (e.g., organization of ships, submarines, aircraft,
weapons, and personnel). Such developments influence the frequency,
duration, intensity, and location of required training and testing
activities. The proposed activities include current activities,
previously analyzed in the 2002 PMSR Environment Impact Statement/
Overseas Environmental Impact Statement (EIS/OEIS), and increases in
the testing and training activities as described in the 2020 PMSR DEIS/
OEIS. NMFS promulgated MMPA incidental take regulations relating to
missile launches from SNI from June 3, 2014, through June 3, 2019 (79
FR 32678; June 6, 2014). Since then, the Navy has been operating under
IHAs (84 FR 28462, June 19, 2019; 85 FR 38863, June 29, 2020) for those
similar activities on SNI. For this rulemaking, the Navy is requesting
authorization for marine mammal take incidental to activities on SNI
similar to those they have conducted under these and previous
authorizations, as well as the use of at-surface and near-surface
explosive detonations throughout the PMSR Study Area. The proposed
testing and training activities are deemed necessary to accomplish
Naval Air System Command's mission of providing for the safe and secure
collection of decision-quality data; and developing, operating,
managing and sustaining the interoperability of the Major Range Test
Facility Base at the PMSR into the foreseeable future.
The Navy's rulemaking/LOA application reflects the most up-to-date
compilation of training and testing activities deemed necessary to
accomplish military readiness requirements. The types and numbers of
activities included in the rule account for fluctuations in training
and testing in order to meet evolving or emergent military readiness
requirements. These proposed regulations would cover training and
testing activities that would occur for a seven-year period beginning
October 2021.
Description of the Specified Activity
The Navy requests authorization to take marine mammals incidental
to conducting training and testing activities. The Navy has determined
that explosive stressors and missile launch activities are most likely
to result in impacts on marine mammals that could rise to the level of
harassment, and NMFS concurs with this determination. Descriptions of
these activities are provided in section 2 of the 2020 PMSR Draft EIS/
OEIS (DEIS/OEIS) (U.S. Department of the Navy, 2020) and in the Navy's
rulemaking/LOA application (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities</a>), and are summarized here.
Dates and Duration
The specified activities would occur at any time during the seven-
year period of validity of the regulations, with the exception of the
activity types and time periods for which limitations have explicitly
been identified (to the maximum extent practicable; see Proposed
Mitigation Measures section). The proposed amount of training and
testing activities are described in the Detailed Description of the
Specified Activities section (Table 3).
Geographical Region
The PMSR Study Area is located adjacent to Los Angeles, Ventura,
Santa Barbara, and San Luis Obispo Counties along the Pacific Coast of
Southern California and includes a 36,000-square-mile sea range (Figure
1). It is a designated Major Range Test Facility Base and is considered
a national asset that exists primarily to provide test and evaluation
information for DoD decision makers and to support the needs of weapon
system development programs and DoD research needs. The two primary
components of the PMSR Study Area are Special Use Airspace (SUA) and
the ocean Operating Areas. Additionally, the Navy is proposing launch
activities on San Nicolas Island (SNI), California, for testing and
training activities associated with operations within the PMSR Study
Area. SNI is one
[[Page 37792]]
of the Channel Islands in the PMSR Study Area.
Special Use Airspace
The SUA is airspace designated wherein activities must be confined
because of their nature, or wherein limitations are imposed upon
aircraft operations that are not a part of those activities, or both.
SUA consists of both controlled and uncontrolled airspace and has
defined dimensions. Flight and other activities for non-participating
aircraft are restricted or prohibited for safety or security reasons.
The majority of SUA is established for military flight activities and,
with the exception of prohibited areas, may be used for commercial or
general aviation when not reserved for military activities. Two area
components of the PMSR SUA:
[ssquf] Warning Areas--A Warning Area is airspace of defined
dimensions, extending from 3 nmi outward from the coast that contains
activity that may be hazardous to non-participating aircraft. Warning
areas are established to contain a variety of hazardous aircraft and
non-aircraft activities, such as aerial gunnery, air and surface
missile firings, bombing, aircraft carrier operations, surface and
subsurface operations, and naval gunfire. The 11 Warning Areas within
the PMSR include W-532N, W-532E, W-532S; W-537; W-289N, W-289 S, W-
289W, W-289E; W-292W, W-292E; and W-412 (see Figure 1).
[ssquf] Restricted Areas--restricted areas are a type of SUA within
which the flight of aircraft, while not wholly prohibited, is subject
to restriction.
Ocean Operating Areas
The PMSR-controlled sea space (Ocean Operating Areas) parallels the
California coast for approximately 225 nmi and extends approximately
180 nmi seaward, aligning with the PMSR Warning Area airspace (Figure
1). The controlled sea space areas consist of the following:
[ssquf] Surface Danger Zones--A danger zone is a defined water area
used for target practice, bombing, rocket firing, or other especially
hazardous military activities.
[ssquf] Restricted Area--A restricted area is a defined water area
for the purpose of prohibiting or limiting public access to the area.
Additional detail can be found in Chapter 2 of the Navy's
rulemaking/LOA application.
BILLING CODE 3510-22-P
[[Page 37793]]
[GRAPHIC] [TIFF OMITTED] TP16JY21.002
BILLING CODE 3510-22-C
Overview of Training and Testing Within the PMSR Study Area
The Navy describes and analyzes the effects of its activities
within the 2020 PMSR DEIS/OEIS. In its assessment, the Navy concluded
that at-surface and near-surface explosive detonations were the
stressors that would result in impacts on marine mammals that could
rise to the level of harassment as defined under the MMPA. Therefore,
the Navy's rulemaking/LOA application provides the Navy's assessment of
potential effects from these stressors in terms of various warfare
mission areas in which they will be conducted.
Primary Mission Areas
The Navy categorizes its at-sea activities into functional warfare
areas called primary mission areas. Each warfare community may train in
some or all of these primary mission areas. The Navy also categorizes
most, but not all, of its testing activities under these primary
mission areas. Activities addressed for the PMSR Study Area are
categorized under three primary mission areas. Within those three
primary mission areas, there are more specific categories or activity
scenarios that reflect testing and training activities, as listed
below: Air warfare (air-to-air, surface-to-air); Electronic warfare
(directed energy--lasers and high-powered microwave systems); and
Surface warfare (surface-to-surface, air-to-surface, and subsurface-to-
surface). A description of the munitions, targets, systems, and other
material used during training and testing activities within these
primary mission areas is provided in Appendix A (Training and Testing
Activities Descriptions) of the 2020 PMSR DEIS/OEIS and summarized
here.
Air warfare--The mission of air warfare is to destroy or reduce
enemy air and missile threats (including unmanned airborne threats) and
serves two purposes: To protect U.S. forces from attacks from the air
and to gain air superiority. Air warfare provides U.S. forces with
adequate attack warnings, while denying hostile forces the ability to
gather intelligence about U.S. forces.
Aircraft conduct air warfare through radar search, detection,
identification,
[[Page 37794]]
and engagement of airborne threats. Surface ships conduct air warfare
through an array of modern anti-aircraft weapon systems such as
aircraft-detecting radar, naval guns linked to radar-directed fire-
control systems, surface-to-air missile systems, and radar-controlled
guns for close-in point defense.
Testing of air warfare systems is required to ensure the equipment
is fully functional under the conditions in which it will be used.
Tests may be conducted on radar and other early-warning detection and
tracking systems, new guns or gun rounds, and missiles. Testing of
these systems may be conducted on new ships and aircraft, and on
existing ships and aircraft following maintenance, repair, or
modification. For some systems, tests are conducted periodically to
assess operability. Additionally, tests may be conducted in support of
scientific research to assess new and emerging technologies. Air-to-air
scenarios involve the employment of an airborne weapon system against
airborne targets. Missiles are fired from a fighter aircraft for both
testing and training events. Surface-to-air scenarios evaluate the
overall weapon system performance, warhead effectiveness, and software/
hardware modifications or upgrades of ground-based and ship-based
weapons systems. Missiles are fired from a ship or a land-based
launcher against a variety of supersonic and subsonic airborne targets.
Electronic Warfare--The mission of electronic warfare is to degrade
the enemy's ability to use electronic systems, such as communication
systems and radar, and to confuse or deny them the ability to defend
their forces and assets. Electronic warfare is also used to detect
enemy threats and counter their attempts to degrade the electronic
capabilities of the Navy. Typical electronic warfare activities include
threat avoidance training, signals analysis for intelligence purposes,
and use of airborne and surface electronic jamming devices (that block
or interfere with other devices) to defeat tracking, navigation, and
communications systems. Testing of electronic warfare systems is
conducted to improve the capabilities of systems and ensure
compatibility with new systems. Testing involves the use of aircraft,
surface ships, and submarine crews to evaluate the effectiveness of
electronic systems. Similar to training activities, typical electronic
warfare testing activities include the use of airborne and surface
electronic jamming devices (including testing chaff and flares; see
Appendix A (PMSR Scenario Descriptions) of the 2020 PMSR DEIS/OEIS for
a description of these devices) to defeat tracking and communications
systems.
Surface Warfare--The mission of surface warfare is to obtain
control of sea space from which naval forces may operate, and entails
offensive action against other surface, subsurface, and air targets
while also defending against enemy forces. In surface warfare, aircraft
use guns, air-launched cruise missiles, or other precision-guided
munitions; ships employ naval guns, and surface-to-surface missiles;
and submarines attack surface ships using submarine-launched, anti-ship
cruise missiles. Surface warfare training includes surface-to-surface
gunnery and missile exercises, air-to-surface gunnery and missile
exercises, and submarine missile launch activities, and other munitions
against surface targets. Testing of weapons used in surface warfare is
conducted to develop new technologies and to assess weapon performance
and operability with new systems, such as unmanned systems. Tests
include various air-to-surface guns and missiles, surface-to-surface
guns and missiles, and bombing tests. Testing activities may be
integrated into training activities to test aircraft or aircraft
systems in the delivery of munitions on a surface target. In most cases
the tested systems are used in the same manner in which they are used
for Fleet training activities. Air-to-surface tests evaluate the
integration of a missile or other weapons system into Department of
Defense aircraft, or the performance of the missile/system itself.
Missiles are fired from an aircraft against a variety of mobile
seaborne targets and fixed aim points.
Summary Testing--Research, Development, Acquisition, Testing, and
Evaluation of new technologies by the U.S. Department of Defense occurs
continually to ensure that the U.S. military can counter new and
anticipated threats. All new Navy systems and related equipment must be
tested to ensure proper functioning before delivery to the Fleets for
use. The PMSR Study Area is the Navy's primary ocean testing area for
guided missiles and related ordnance. Test operations on the PMSR Study
Area are conducted under highly controlled conditions, allowing for the
collection of empirical data to evaluate the performance of a weapon
system or subsystem. Testing conducted in the PMSR Study Area is
important for maintaining readiness. Two of the U.S. Navy's Systems
Commands, Naval Sea Systems Command (NAVSEA) and Naval Air Systems
Command (NAVAIR), sponsor the majority of the testing within the PMSR
Study Area. NAVSEA's five affiliated Program Executive Offices (PEOs)
oversee over a dozen Program Manager, Sea offices that sponsor testing
activities within the PMSR Study Area. NAVAIR's four affiliated PEOs,
along with NAVAIR Headquarters-managed programs, oversee approximately
20 Program Managers and Air offices that also sponsor testing
activities at PMSR.
Target and Missile Launches on SNI--The Navy plans to continue a
target and missile launch program from two launch sites on SNI for
testing and training activities associated with operations within the
PMSR Study Area. Missiles vary from tactical and developmental weapons
to target missiles used to test defensive strategies and other weapons
systems. Some launch events involve a single missile or target, while
others involve the launch of multiple missiles or targets in quick
succession. The missiles or targets are launched from one of several
fixed locations on the western end of SNI. Missiles or targets launched
from SNI fly generally west, southwest, and northwest through the PMSR
Study Area. The primary launch locations are the Alpha Launch Complex,
located 190 meters (m) above sea level on the west-central part of SNI
and the Building 807 Launch Complex, which accommodates several fixed
and mobile launchers, at the western end of SNI at approximately 11 m
above sea level. The Point Mugu airfield on the mainland, the airfield
on SNI, and the target sites in the PMSR will be a routine part of
launch operations.
Description of Stressors
The Navy uses a variety of platforms, weapons, and other devices,
including ones used to ensure the safety of Sailors and Marines, to
meet its mission. Training and testing with these systems may introduce
acoustic (sound) energy or shock waves from explosives into the
environment. The following subsections describe explosives detonated at
or near the surface of the water and launch noise associated with
missiles launched from SNI for marine mammals and their habitat
(including prey species) within the PMSR Study Area. Because of the
complexity of analyzing sound propagation in the ocean environment, the
Navy relied on acoustic models in its environmental analyses and
rulemaking/LOA application that considered sound source characteristics
and varying ocean conditions across the PMSR Study Area. Stressor/
resource interactions that were determined to have de minimis or no
impacts (i.e., vessel, aircraft, or weapons noise) were
[[Page 37795]]
not carried forward for analysis in the Navy's rulemaking/LOA
application. NMFS reviewed the Navy's analysis and conclusions on de
minimis sources and finds them complete and supportable.
Acoustic stressors include incidental sources of broadband sound
produced as a byproduct of vessel movement and use of weapons or other
deployed objects. Explosives also produce broadband sound but are
characterized separately from other acoustic sources due to their
unique hazardous characteristics. There are no sonar activities
proposed in the PMSR Study Area. Characteristics of explosives are
described below.
In order to better organize and facilitate the analysis of various
explosives used for training and testing by the Navy, including sonar
and other transducers and explosives, a series of source
classifications, or source bins, was developed by the Navy. The source
classification bins do not include the broadband sounds produced
incidental to vessel or aircraft transits, weapons firing, and bow
shocks.
The use of source classification bins provides the following
benefits:
[ssquf] Provides the ability for new sensors or munitions to be
covered under existing authorizations, as long as those sources fall
within the parameters of a bin;
[ssquf] Improves efficiency of source utilization data collection
and reporting requirements anticipated under the MMPA authorizations;
[ssquf] Ensures a conservative approach to all impact estimates, as
all sources within a given class are modeled as the most impactful
source (having the largest net explosive weight) within that bin;
[ssquf] Allows analyses to be conducted in a more efficient manner,
without any compromise of analytical results; and
[ssquf] Provides a framework to support the reallocation of source
usage (number of explosives) between different source bins, as long as
the total numbers of takes remain within the overall analyzed and
authorized limits. This flexibility is required to support evolving
Navy training and testing requirements, which are linked to real world
events.
Explosives
This section describes the characteristics of explosions during
naval training and testing. The activities analyzed in the Navy's
rulemaking/LOA application that use explosives are described in
Appendix A (PMSR Scenario Descriptions) of the 2020 PMSR DEIS/OEIS.
To more completely analyze the results predicted by the Navy's
acoustic effects model from detonations occurring in-air above the
ocean surface, it is necessary to consider the transfer of energy
across the air-water interface.
Detonation of an explosive in air creates a supersonic high
pressure shock wave that expands outward from the point of detonation
(Kinney & Graham, 1985; Swisdak, 1975). The near-instantaneous rise
from ambient pressure to an extremely high peak pressure is what makes
the explosive shock wave potentially injurious to an animal
experiencing the rapid pressure change (U.S. Department of the Navy,
2017e). Farther from an explosive, the peak pressures decay and the
explosive waves propagate as an impulsive, broadband sound. As the
shock wave-front travels away from the point of detonation, it slows
and begins to behave as an acoustic wave-front travelling at the speed
of sound. Whereas a shock wave from a detonation in-air has an abrupt
peak pressure, that same pressure disturbance when transmitted through
the water surface results in an underwater pressure wave that begins
and ends more gradually compared with the in-air shock wave, and
diminishes with increasing depth and distance from the source (Bolghasi
et al., 2017; Chapman and Godin, 2004; Cheng and Edwards, 2003; Moody,
2006; Richardson et al., 1995; Sawyers, 1968; Sohn et al., 2000;
Swisdak, 1975; Waters and Glass, 1970; Woods et al., 2015). The
propagation of the shock wave in air and then transitioning underwater,
is very different from a detonation occurring deep underwater where
there is little interaction with the surface. In the case of an
underwater detonation occurring just below the surface, a portion of
the energy from the detonation would be released into the air (referred
to as surface blow off), and at greater depths a pulsating, air-filled
cavitation bubble would form, collapse, and reform around the
detonation point (Urick, 1983). The Navy's acoustic effects model for
analyzing underwater impacts on marine species does not account for the
loss of energy due to surface blow-off or cavitation at depth. Both of
these phenomena would diminish the magnitude of the acoustic energy
received by an animal under real-world conditions (U.S. Department of
the Navy, 2018c).
Propagation of explosive pressure waves in water is highly
dependent on environmental characteristics such as bathymetry, bottom
type, water depth, temperature, and salinity, which affect how the
pressure waves are reflected, refracted, or scattered; the potential
for reverberation; and interference due to multi-path propagation. In
addition, absorption greatly affects the distance over which higher-
frequency components of explosive broadband noise can propagate.
Because of the complexity of analyzing sound propagation in the ocean
environment, the Navy relies on acoustic models in its environmental
analyses that consider sound source characteristics and varying ocean
conditions across the PMSR Study Area (U.S. Department of the Navy,
2019a).
Missiles, rockets, bombs, and medium and large-caliber projectiles
may be explosive or nonexplosive, depending on the objective of the
testing or training activity in which they are used. The proposed
activities do not include explosive munitions used underwater.
Missiles, bombs, and projectiles that detonate at or near (within 10 m
of) the water's surface are considered for the potential impact they
may have on marine mammals. All explosives used during testing and
training activities within the PMSR Study Area would detonate at or
near the surface or in-air. Several parameters influence the acoustic
effect of an explosive: The weight of the explosive warhead, the type
of explosive material, the boundaries and characteristics of the
propagation medium(s); and the detonation depth underwater and the
depth of the receiver (i.e., marine mammal). The net explosive weight
(NEW), which is the explosive power of a charge expressed as the
equivalent weight of trinitrotoluene (TNT), accounts for the first two
parameters.
Land-Based Launch Noise on San Nicolas Island
Noise from target and missile launches on SNI can also occur. These
ongoing activities affecting pinnipeds hauled out in the vicinity of
launch sites have been analyzed previously (NMFS 2014, 2019, 2020) and
are summarized below as part of the Navy's rulemaking/LOA application.
As part of previous authorizations, the Navy could conduct up to 40
launch events annually from SNI, but the total may be less than 40
depending on operational requirements. Launch timing will be determined
by operational, meteorological, and logistical factors. Up to 10 of the
40 launches may occur at night, but this is also dependent on
operational requirements, and night-time launches are only conducted
when required by test objectives.
[[Page 37796]]
Vessel Strike
Vessel strikes have the potential to result in incidental take from
serious injury and/or mortality. Vessel strikes are not specific to any
particular training or testing activity, but rather are a limited,
sporadic, and incidental result of Navy vessel movement within a study
area. Vessel strikes from commercial, recreational, and military
vessels are known to seriously injure and occasionally kill cetaceans
(Abramson et al., 2011; Berman-Kowalewski et al., 2010; Calambokidis,
2012; Douglas et al., 2008; Laggner, 2009; Lammers et al., 2003; Van
der Hoop et al., 2012; Van der Hoop et al., 2013), although reviews of
the literature on ship strikes mainly involve collisions between
commercial vessels and whales (Jensen and Silber, 2003; Laist et al.,
2001). Vessel speed, size, and mass are all important factors in
determining both the potential likelihood and impacts of a vessel
strike to marine mammals (Conn and Silber, 2013; Gende et al., 2011;
Silber et al., 2010; Vanderlaan and Taggart, 2007; Wiley et al., 2016).
For large vessels, speed and angle of approach can influence the
severity of a strike.
The number of Navy vessels in the PMSR Study Area at any given time
varies and is dependent on scheduled testing and training requirements.
Most activities include either one or two vessels and may last from a
few hours to two weeks. Vessel movement as part of the proposed
activities would be widely dispersed throughout the PMSR Study Area.
Vessels used include ships (e.g., aircraft carriers, surface
combatants), support craft, and submarines. Vessel size ranges from 15
ft to over 1,000 ft, and vessels transit at speeds that are optimal for
fuel conservation or to meet operational requirements. In comparison,
commercial ship size can range from very large oil tankers that are
over 1,000 ft in length to the smaller general cargo ships with lengths
that can be under 300 ft. Large Navy ships (greater than 18 m in
length) generally operate at average speeds of 10-15 knots, and
submarines generally operate at speeds in the range of 8-13 knots.
Small Navy craft (for purposes of this discussion, less than 18 m in
length), which are all support craft, have much more variable speeds
(0-50+ knots, dependent on the mission). While these speeds are
averages that are representative of most events, some vessels need to
operate outside of these parameters. For example, to produce the
required relative wind speed over the flight deck, an aircraft carrier
engaged in flight operations must adjust its speed through the water
accordingly. Also, there are other instances, such as launch and
recovery of a small rigid-hull inflatable boat, or retrieval of a
target when vessels would be dead in the water, or moving slowly ahead
to maintain steerage. There are a few specific testing and training
events that include high-speed requirements for certain systems for
which vessels would operate at higher speeds.
Refer to Chapter 3, Affected Environment and Environmental
Consequences of the 2020 PMSR DEIS/OEIS for additional details on
vessel use and movement in the PMSR Study Area.
Detailed Description of the Specified Activities
Proposed Training and Testing Activities
Training and testing activities would be conducted at sea, in
designated airspace, and on SNI, within the PMSR Study Area.
The proposed training and testing activities are deemed necessary
to accomplish Naval Air Systems Command's mission of providing for the
safe and secure collection of decision-quality data; and developing,
operating, managing and sustaining the interoperability of the Major
Range Test Facility Base at the PMSR into the foreseeable future.
Collectively, the proposed training and testing activities support
current and projected military readiness requirements into the
foreseeable future, as shown in Table 1.
Table 1--Maximum Number of Annual Proposed Activities in the PMSR Study
Area
[Inclusive of SNI launches]
------------------------------------------------------------------------
Proposed
Activity Activity sub category activities
------------------------------------------------------------------------
Aerial Targets (# of targets).. ....................... 176
Surface Targets (# of targets). ....................... 522
Ordnance (# of ordnance)....... Bombs.................. 30
Gun Ammunition......... 281,230
Missiles............... 584
Rockets................ 40
------------------------------------------------------------------------
Most of the factors influencing frequency and types of activities
are fluid in nature (i.e., continually evolving and changing), and the
annual activity level in the PMSR Study Area will continue to
fluctuate. The number of events may not be the same year to year, but
the maximum number of events were predicted annually. Total annual
events would not exceed what is proposed in Table 1 above. Proposed
training and testing duration and frequency varies depending on Fleet
requirements, and funding and does not occur on a predictable annual
cycle.
Fleet training activities occur over scheduled continuous and
uninterrupted blocks of time, focusing on the development of core
capabilities/skills. Training events in the PMSR Study Area are
conducted to ensure Navy forces can sustain their training cycle
requirements. Primarily, changes occur with increases or decreases in
annual operational tempo of activities, in addition to changes in the
types of aircraft, vessels, targets, ordnance, and tasks that are
actions or processes performed as part of Navy operations.
Future testing depends on scientific and technological developments
that are not easy to predict, and experimental designs may evolve with
emerging science and technology. Even with these challenges, the Navy
makes every effort to forecast all future testing requirements. As a
result, testing requirements are driven by the need to support Fleet
readiness based on emerging national security interests, and
alternatives must have sufficient annual capacity to conduct the
research, development, and testing of new systems and technologies,
with upgrades, repairs, and maintenance of existing systems.
Fleet Training
Fleet training within the PMSR Study Area includes the same types
of warfare of the primary mission areas. Training conducted in
conjunction with testing activities provide Fleet operators unique
opportunities to train with ship and
[[Page 37797]]
aircraft combat weapon systems and personnel in scripted warfare
environments, including live-fire events. For example, Fleet training
would occur while testing a weapon system, in which Sailors would
experience (be trained in) the use of the system being tested. Combat
ship crews train in conjunction with scheduled ship testing and
qualification trials, to take advantage of the opportunity to provide
concurrent training and familiarization for ship personnel in
maintaining and operating installed equipment, identifying design
problems, and determining deficiencies in support elements (e.g.,
documentation, logistics, test equipment, or training). Live and inert
weapons, along with chaff, flares, jammers, and lasers may be used.
Typically concurrent with testing, surface training available
within the PMSR Study Area includes tracking events, missile-firing
events, gun-firing events, high-speed anti-radiation missile events,
and shipboard self-defense system training, (e.g., Phalanx (Close-in
Weapons System), Rolling Airframe Missile, and Evolved Sea Sparrow
Missile). These events are limited in scope and generally focus on one
or two tasks. Missiles may be fired against subsonic, supersonic, and
hypersonic targets. Certain training events designed for single ships
are conducted to utilize unique targets only available for training in
the PMSR Study Area.
Aviation warfare training conducted in the PMSR Study Area,
categorized as unit-level training, is designed for a small number of
aircraft up to a squadron of aircraft. These training events occur
within the PMSR Study Area, as it is the only West Coast Navy venue to
provide powered air-to-air targets. They are limited in scope and
generally focus on one or two tasks. These scenarios require planning
and coordination to ensure safe and effective training.
Combat Systems Testing
The System Command Program Executive Offices are tasked with
conducting extensive combat systems tests and trials on each new
platform prior to releasing the platform to the Fleet, to include ships
that have been in an extended upgrade or overhaul status. The PMSR
Study Area is the preferred site to conduct these tests, as it offers a
venue for a thorough evaluation of combat and weapons system
performance through the actual employment of weapon systems. The
comprehensive tests are conducted by the responsible Program Manager,
with close cooperation from the Fleet Type Commanders (Surface Force,
Air Force, or Submarine Force). Frequent tests conducted in the PMSR
Study Area are Combat Systems Ship Qualification Trials (CSSQTs). This
is a series of comprehensive tests and trials designed to show that the
equipment and systems included in the CSSQT program meet combat system
requirements. Live and inert weapons, along with chaff, flares,
jammers, and lasers may be used. Naval Sea Systems Command has recently
developed two new reporting programs to test and evaluate combat and
weapons system performance on new classes of ships, resulting in an
increased tempo in the PMSR Study Area.
Explosives At-Surface or Near the Surface
Missiles, bombs, and projectiles that detonate at or near (within
10 m of) the water's surface are considered for the potential that they
could result in an acoustic impact to marine mammals that may be
underwater and nearby. The maximum number of explosives and the
appropriate events modeling bin for the proposed activities are
provided in Table 2 for the proposed activities in the PMSR Study Area.
Table 2 describes the maximum number of explosives that could be used
in any year under the proposed training and testing activities. Under
the proposed activities, bin use could vary annually (but would not
exceed the maximum), and the seven-year totals for the proposed
training and testing activities take into account that annual
variability.
Table 2--Explosives Detonating at or Near the Surface by Bins Annually and for a Seven-Year Period for Training
and Testing Activities Within the PMSR Study Area
[Inclusive of SNI Launches]
----------------------------------------------------------------------------------------------------------------
Maximum number
Maximum number of high
of high explosives
Primary mission area activity Explosive bin Munition type explosive used over a 7-
scenarios munitions used year period
annually proposed
activity
----------------------------------------------------------------------------------------------------------------
Surface-Surface.................... E1 Gunnery.............. 22,110 154,770
E3 Gunnery.............. 4,909 34,363
E5 Gunnery.............. 1,666 11,662
Air-Surface........................ E5 Rockets.............. 24 168
Air-Surface; Surface-Air........... E6 Missiles............. 72 504
Air-Surface........................ E7 Missiles, Bombs...... 45 315
Air-Surface; Surface-Air........... E8 Missiles............. 45 315
Air-Surface; Surface-Surface....... E9 Missiles, Bombs, 58 406
Rockets.
Surface-Surface; Subsurface-Surface E10 Missiles............. 13 91
----------------------------------------------------------------------------------------------------------------
Note: Bins E1-E5 are gunnery events that involve guns with high rates of firing ``clusters'' of munitions (e.g.,
>80-200 rounds per minute for Bin E1, 500-650 rounds per minute for Bin E3, and 16-20 rounds per minutes for
Bin E5), hence the high number of HE munitions used during these activities. The numbers above do not reflect
the actual number of events, which can vary and typically last 1-3 hrs. The increase in tempo under the
Proposed Action is a result of a proposed increase in Combat Systems Ship Qualification Trials as discussed in
Section 2.2.1 (Current and Proposed Activities) of the 2020 PMSR DSEIS/OEIS.
The explosive energy released by detonations in air has been well
studied, and basic methods are available to estimate the explosive
energy exposure with distance from the detonation (e.g., U.S.
Department of the Navy, 1975). In air, the propagation of impulsive
noise from an explosion is highly influenced by atmospheric conditions,
including temperature and wind. While basic estimation methods do not
consider the unique environmental conditions that
[[Page 37798]]
may be present on a given day, they allow for approximation of
explosive energy propagation under neutral atmospheric conditions.
Explosions that occur during air warfare would typically be at a
sufficient altitude that a large portion of the sound refracts upward
due to cooling temperatures with increased altitude. Based on an
understanding of the explosive energy released by detonations in air,
detonations occurring in air at altitudes greater than 10 m are not
likely to result in acoustic impacts to marine mammals and thus are not
carried forward in the analysis.
Missile Launch Activities on SNI
Missiles can be propelled by either liquid-fueled or solid-fueled
rocket engines; however, solid fuel is preferred for military uses.
Such engines commonly propel tactical guided missiles (i.e., missiles
intended for use within the immediate area) toward their targets at
twice the speed of sound. Cruise or ballistic missiles are designed to
strike targets far beyond the immediate area, and are therefore also
known as strategic missiles. Cruise missiles are jet-propelled at
subsonic speeds throughout their flights, while ballistic missiles are
rocket-powered only in the initial (boost) phase of flight, after which
they follow an arcing trajectory to the target. As gravity pulls the
ballistic warhead back to Earth, speeds of several times the speed of
sound are reached. Ballistic missiles are most often categorized as
short-range, medium-range, intermediate-range, and intercontinental
ballistic missiles. Missile weights range between 54-2,900 kilograms
(kg), but total weight is dependent on fuel or boosters.
Table 3 shows the number of launches that have occurred at SNI
since 2001 and the number of launch events that have occurred during
the associated comprehensive reporting timeframes. There have not been
more than 25 launch events conducted in any given year since 2001.
However, as part of the proposed activities, 40 launch events per year
from SNI involving various missiles and aerial targets are requested
for take authorization.
Table 3--The Total Number of Launches That Have Occurred Since 2001 at
SNI
------------------------------------------------------------------------
Number of
Time period launches
------------------------------------------------------------------------
August 2001 to March 2008............................... 77
June 2009 to June 2014.................................. 36
June 2014 to June 2019.................................. 27
------------------------------------------------------------------------
A combination of missiles and targets are launched from SNI,
including aerial targets, surface-to-surface missiles, and surface-to-
air missiles, with aerial targets representing the majority of the
launches from SNI.
The following descriptions are representative of some of the types
of targets and missiles typically launched from SNI. While this list is
not inclusive of all potential missiles and targets that could be
launched annually, the descriptions and the sound profiles are
representative of the diversity of the types of missiles and targets
typically launched. For information on the sound levels these missiles
produce please refer to Section 1.2 of the application.
GQM-163A ``Coyote''--The Coyote, designated GQM-163A, is an
expendable Supersonic Sea-Skimming Target (SSST) powered by a ducted-
rocket ramjet. This missile is designed to provide a ground-launched,
aerial target system to simulate a supersonic, sea-skimming Anti-Ship
Cruise missile threat. Coyote launches are expected to be the primary
large missile launched from SNI over the next several years. Coyotes
are launched from previously installed launchers at the inland location
(Alpha Launch Complex) on SNI.
Standard Missile (SM-2, SM-3, SM-6)--The Standard family of
missiles consists of a range of air defense missiles including
supersonic, medium, and extended range surface-to-air and surface-to-
surface missiles. The Standard Missile 3 Block IIA (SM-3) is a ship-
based missile system used to intercept short- to intermediate-range
ballistic missiles as a part of the Aegis Ballistic Missile Defense
System. Although primarily designed as an antiballistic missile
defensive weapon, the SM-3 has also been employed in an anti-satellite
capacity against a satellite at the lower end of low Earth orbit.
Similarly, the SM-6 is a vertically launched, extended range missile
compatible with the Aegis Weapon System to be used against extended
range threats. The SM-6 Block I/IA combines the tested legacy of the
SM-2 propulsion system and warhead with an active radio frequency
seeker modified from the AIM-120 Advanced Medium Range Air-to-Air
Missile. The new features allow for over-the-horizon engagements,
enhanced capability at extended ranges and increased firepower. To
date, only the SM-3 has been launched from SNI.
Other Missiles That May Be Used During Launch Events--The Navy may
also launch other missiles to simulate various types of threat missiles
and aircraft and to test other systems. For example, Tactical Tomahawks
were launched from Building 807 Launch Complex in 2018 and 2019. Under
this proposed rule, missiles launched from SNI would have sound source
levels the same or lower than missiles described above or previously
launched from the island.
Vessel Movement
The number and type of scheduled Navy vessels or Navy support
vessels operating within the PMSR Study Area depends on the
requirements for mission-essential activities, such as the test and
evaluation of new weapon systems or qualification trials for upgraded
existing ships. The types of Navy vessels or Navy support vessels
operating within the PMSR are highly variable and range from small work
boats used for nearshore work to major Navy combatants, up to and
including aircraft carriers. Navy activities are conducted in large
subdivisions of the total PMSR Study Area, and blocks of range times
are allocated based on activity requirements. Most activities include
either one or two vessels and may last from a few hours to two weeks.
Vessel movement as part of the proposed activities would be widely
dispersed throughout the PMSR Study Area.
The PMSR Study Area military vessel activity can be divided into
two categories: Project ships and support boats. Project ships are
larger Navy combatant vessels, such as destroyers, cruisers, or any
other commissioned Navy or foreign military ship directly involved in
events. They may operate anywhere within the PMSR Study Area depending
on activity needs, although most ship operations occur within 60
nautical miles (nmi) of SNI. Most project ships and scheduled training
ships operating in the PMSR Study Area transit there from off-range
(e.g., San Diego). Support boats are smaller vessels directly involved
in test activities and operate from the Port Hueneme Harbor. While they
may also operate throughout the PMSR Study Area, support boat
operations occur mainly within the range areas receiving the most use.
Smaller support boats have limited range and usually operate close to
shore near Point Mugu and SNI. The activity level of ships or boats is
characterized by a ship or boat event.
The Navy tabulated annual at-sea vessel steaming days for training
and testing activities projected for the PMSR Study Area. Approximately
333 annual events of Navy at-sea vessel usage will occur over 2,085
hours (approximately 87 at-sea days) in the PMSR Study Area (Table 4).
In comparison to the Southern
[[Page 37799]]
California portion (SOCAL) of the Hawaii-Southern California Training
and Testing (HSTT) Study Area, the estimated number of annual at-sea
days in the PMSR Study Area is less than 3 percent of what occurs in
SOCAL annually.
Table 4--Annual At-Sea Vessel Steaming Days for Training and Testing Activities Projected for the PMSR Study
Area
----------------------------------------------------------------------------------------------------------------
Proposed activity
Vessel Ship type -------------------------------
Events Hours
----------------------------------------------------------------------------------------------------------------
CG......................................... Guided Missile Cruiser............. 41 275
DDG-51..................................... Guided Missile Destroyer........... 36 132
LHA........................................ Amphibious Assault Ship............ 40 200
SDTS....................................... Self-Defense Test Ship............. 50 190
WMSL-751/OPC............................... Coast Guard Cutter................. 6 28
LCS Variant (LCS 1)........................ Littoral Combat Ship............... 40 360
LCS Variant (LCS 2)........................ 40 360
FF......................................... Future Frigate..................... 40 360
DDG 1000 Zumwalt Class..................... Guided Missile Destroyer........... 3 30
LHD........................................ Amphibious Assault Ship............ 4 13
LPD........................................ Amphibious Transport Deck.......... 4 13
LSD........................................ Dock Landing Ship.................. 4 13
CVN........................................ Nuclear-Powered Aircraft Carrier... 6 16
SSBN....................................... Ballistic Missile Submarine........ 19 95
-------------------------------
Total.................................. 333 2,085
----------------------------------------------------------------------------------------------------------------
Additional details on Navy at-sea vessel movement are provided in
the 2020 PMSR DEIS/OEIS.
Standard Operating Procedures
For training and testing to be effective, personnel must be able to
safely use their sensors and weapon systems as they are intended to be
used in military missions and combat operations and to their optimum
capabilities. Navy publishes or broadcasts standard operating
procedures via numerous naval instructions and manuals, including but
not limited to the following:
<bullet> Ship, submarine, and aircraft safety manuals;
<bullet> Ship, submarine, and aircraft standard operating manuals;
<bullet> Fleet Area Control and Surveillance Facility range
operating instructions;
<bullet> Fleet exercise publications and instruction;
<bullet> Naval Air Warfare Center Weapons Division (NAWCWD) and
Naval Sea Systems Command test range safety and standard operating
instructions;
<bullet> Navy instrumented range operating procedures;
<bullet> Naval shipyard sea trial agendas;
<bullet> Research, development, test, and evaluation plans;
<bullet> Naval gunfire safety instructions;
<bullet> Navy planned maintenance system instructions and
requirements;
<bullet> Federal Aviation Administration regulations;
<bullet> International Regulations for Preventing Collisions at
Sea;
<bullet> Range safety standard operating procedures and
instructions for explosive munitions; and
<bullet> Ammunition and Explosive Operations standard operating
procedures.
Because standard operating procedures are essential to safety and
mission success, the Navy considers them to be part of the proposed
Specified Activities, and has included them in the environmental
analysis (see Chapter 3, Affected Environment and Environmental
Consequences, of the 2020 PMSR DSEIS/OEIS for further details).
Description of Marine Mammals and Their Habitat in the Area of the
Specified Activities
Marine mammal species that have the potential to occur in the PMSR
Study Area are presented in Table 5 along with an abundance estimate,
an associated coefficient of variation value, and best and minimum
abundance estimates. The Navy requests authorization to take
individuals of marine mammal species by Level A and Level B harassment
incidental to training and testing activities from detonations of
explosives occurring at or near the surface and launch activities on
SNI (Table 5).
Information on the status, distribution, abundance, population
trends, habitat, and ecology of marine mammals in the PSMR Study Area
also may be found in Section 4 of the Navy's rulemaking/LOA
application. NMFS reviewed this information and found it to be accurate
and complete. Additional information on the general biology and ecology
of marine mammals is included in the 2020 PMSR DEIS/OEIS. Table 5
incorporates data from the U.S. Pacific and the Alaska Marine Mammal
Stock Assessment Reports (SARs; Carretta et al., 2019; Muto et al.,
2019) and the most recent revised data in the draft SARs (see <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>). Table 5 also incorporates the best
available science, including monitoring data from the Navy's marine
mammal research efforts.
Species Not Included in the Analysis
The species carried forward for analysis (and described in Table 5
below) are those likely to be found in the PMSR Study Area based on the
most recent data available, and do not include species that may have
once inhabited or transited the area but have not been sighted in
recent years (e.g., species which were extirpated from factors such as
19th and 20th century commercial exploitation). Several species that
may be present in the northwest Pacific Ocean have a low probability of
presence in the PMSR Study Area. These species are considered
extralimital (not anticipated to occur in the Study Area) or rare
(occur in the Study Area sporadically, but sightings are rare). Species
unlikely to be present in the PMSR Study Area or that are rare include
the North Pacific right whale (Eubalaena japonica), rough-toothed
dolphin (Steno bredanensis), and Steller sea lion
[[Page 37800]]
(Eumetopias jubatus), and these species have all been excluded from
subsequent analysis for the reasons described below. There have been
only four sightings, each of a single Northern Pacific right whale, in
Southern California waters over approximately the last 30 years (in
1988, 1990, 1992, and 2017) (Brownell et al., 2001; Carretta et al.,
1994; National Marine Fisheries Service, 2017b; WorldNow, 2017).
Sightings off California are rare, and historically, even during the
period of U.S. West Coast whaling through the 1800s, right whales were
considered uncommon to rare off California (Reeves and Smith, 2010;
Scammon, 1874). The range of the rough-toothed dolphin is known to
occasionally include the Southern California coast during periods of
warmer ocean temperatures, but there is no recognized stock for the
U.S. West Coast (Carretta et al., 2019c). Several strandings were
documented for this species in central and Southern California between
1977 and 2002 (Zagzebski et al., 2006), but this species has not been
observed during seven systematic ship surveys from 1991 to 2014 off the
U.S. West Coast (Barlow, 2016). During 16 quarterly ship surveys off
Southern California from 2004 to 2008, there was one encounter with a
group of nine rough-toothed dolphins, which was considered an
extralimital occurrence (Douglas et al., 2014). Steller sea lions range
along the north Pacific from northern Japan to California (Perrin et
al., 2009b), with centers of abundance and distribution in the Gulf of
Alaska and Aleutian Islands (Muto et al., 2019). San Miguel Island and
Santa Rosa Island were, in the past, the southernmost rookeries and
haulouts for the Steller sea lions, but their range contracted
northward in the 20th century, and now A[ntilde]o Nuevo Island off
central California is currently the southernmost rookery (Muto et al.,
2019; National Marine Fisheries Service, 2008; Pitcher et al., 2007).
Steller sea lions pups were known to be born at San Miguel Island up
until 1981 (National Marine Fisheries Service, 2008; Pitcher et al.,
2007), and so, as the population continues to increase, it is
anticipated that the Steller sea lions may re-establish a breeding
colony on San Miguel Island in the future. In the Channel Islands and
vicinity, despite the species' general absence from the area, a
consistent but small number of Steller sea lions (one to two
individuals at a time) have been sighted in recent years. Aerial
surveys for pinnipeds in the Channel Islands from 2011 to 2015
encountered a single Steller sea lion at SNI in 2013 (Lowry et al.,
2017). NMFS agrees with the Navy's assessment that these species are
unlikely to occur in the PMSR Study Area and they are not discussed
further.
Southern sea otter (Enhydra lutris neris) occurs nearshore off the
coast of central California, ranging from Half Moon Bay in the north to
Point Conception and at SNI (Tinker et al., 2006; Tinker and Hatfield,
2016; U.S. Geological Survey, 2014). Southern sea otters are managed by
the U.S. Fish and Wildlife Service and therefore are not discussed
further.
Table 5--Marine Mammal Occurrence Within the PMSR Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Status Stock abundance
---------------------------------------- (CV)/Nmin; most
Common name Scientific name Stock recent abundance PBR \3\ Annual M/
\1\ MMPA ESA survey \2\ SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale..................... Balaenoptera Eastern North Depleted.......... Endangered........ 1,496 (0.44)/ 1.2 >=19.4
musculus. Pacific. 1,051; 2014.
Bryde's whale.................. Balaenoptera Eastern Tropical .................. .................. unk; na.......... unk unk
brydei/edeni. Pacific.
Fin whale...................... Balaenoptera California, Depleted.......... Endangered........ 9,029 (0.12)/ 81 >=43.7
physalus. Oregon, and 8,127; 2014.
Washington.
Gray whale..................... Eschrichtius Eastern North .................. .................. 26,960 (0.05)/ 801 131
robustus. Pacific. 25,849; 2016.
Western North Depleted.......... Endangered........ 290 (na)/271; 0.12 unk
Pacific. 2016.
Humpback whale................. Megaptera California, Depleted.......... Threatened/ 2,900 (0.05)/ 16.7 >=42.1
novaeangliae. Oregon, Endangered \1\. 2,784; 2019.
Washington.
Minke whale.................... Balaenoptera California, .................. .................. 636 (0.72)/369; 3.5 >=1.3
acutorostrata. Oregon, and 2014.
Washington.
Sei whale...................... Balaenoptera Eastern North Depleted.......... Endangered........ 519 (0.4)/374; 0.75 >=0.2
borealis. Pacific. 2014.
Baird's beaked whale........... Berardius bairdii. California, .................. .................. 2,697 (0.6)/ 16 0
Oregon, and 1,633; 2014.
Washington.
Common Bottlenose dolphin...... Tursiops truncatus California Coastal .................. .................. 453 (0.06)/346; 2.7 >=2.0
2011.
California, .................. .................. 1,924 (0.54)/ 11 >=1.6
Oregon, and 1,255; 2014.
Washington
Offshore.
Cuvier's beaked whale.......... Ziphius California, .................. .................. 3,274 (0.67)/ 21 <0.1
cavirostris. Oregon, and 2,059; 2014.
Washington.
Dall's porpoise................ Phocoenoides dalli California, .................. .................. 25,750 (0.45)/ 172 0.3
Oregon, and 17,954; 2014.
Washington.
Dwarf sperm whale.............. Kogia sima........ California, .................. .................. unk; 2014........ und 0
Oregon, and
Washington.
Harbor Porpoise................ Phocoena phocoena. Morro Bay......... .................. .................. 2,917 \5\ (0.41)/ \5\ 66 \5\ >=0.4
1,384; 2012.
Killer whale................... Orcinus orca...... Eastern North .................. .................. 300 (0.10)/276; 2.8 0
Pacific Offshore. 2012.
Eastern North .................. .................. 349 na/349; 2018. 3.5 0.4
Pacific Transient/
West Coast
Transient \6\.
Long-beaked common dolphin..... Delphinus capensis California........ .................. .................. 101,305 (0.49)/ 657 >=35.4
68,432; 2014.
Mesoplodont beaked whales \7\.. Mesoplodon spp.... California, .................. .................. 3,044 (0.54)/ 20 0.1
Oregon, and 1,967; 2014.
Washington.
Northern right whale dolphin... Lissodelphis California, .................. .................. 26,556 (0.44)/ 179 3.8
borealis. Oregon, and 18,608; 2014.
Washington.
Pacific white-sided dolphin.... Lagenorhynchus California, .................. .................. 26,814 (0.28)/ 191 7.5
obliquidens. Oregon, and 21,195; 2014.
Washington.
[[Page 37801]]
Pygmy sperm whale.............. Kogia breviceps... California, .................. .................. 4,111 (1.12)/ 19 0
Oregon, and 1,924; 2014.
Washington.
Risso's dolphins............... Grampus griseus... California, .................. .................. 6,336 (0.32)/ 46 >=3.7
Oregon, and 4,817; 2014.
Washington.
Short-beaked common dolphin.... Delphinus delphis. California, .................. .................. 969,861 (0.17)/ 8,393 >=40
Oregon, and 839,325; 2014.
Washington.
Short-finned pilot whale....... Globicephala California, .................. .................. 836 (0.79)/466; 4.5 1.2
macrorhynchus. Oregon, and 2014.
Washington.
Sperm whale.................... Physeter California, Depleted.......... Endangered........ 1,997 (0.57)/ 2.5 0.6
macrocephalus. Oregon, and 1,270; 2014.
Washington.
Striped dolphin................ Stenella California, .................. .................. 29,211 (0.20)/ 238 >=0.8
coeruleoalba. Oregon, and 24,782; 2014.
Washington.
Harbor seal.................... Phoca vitulina.... California........ .................. .................. 30,968 na/27,348; 1,641 43
2012.
Northern elephant seal......... Mirounga California........ .................. .................. 179,000 na/ 4,882 8.8
angustirostris. 81,368; 2010.
California sea lion............ Zalophus U.S. Stock........ .................. .................. 257,606 na/ 14,011 >=321
californianus. 233,515; 2014.
Northern fur seal.............. Callorhinus California........ .................. .................. 14,050 na/7,524; 451 1.8
ursinus. 2013.
Guadalupe fur seal............. Arctocephalus Mexico to Depleted.......... Threatened........ 34,187 unk/ 1,602 >=3.8
townsendi. California. 31,109; 2013.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Taxonomy follows Committee on Taxonomy (2018).
\2\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. The most recent abundance survey that is reflected in the abundance
estimate is presented; there may be more recent surveys that have not yet been incorporated into the estimate.
\3\ PBR is the Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a range.
\5\ The abundance number as presented is from the ``fine-scale transects'' as documented in Forney et al. (2014). PBR and M/SI are from draft 2020 SAR
for the Pacific (Carretta et al., 2020).
\6\ This stock is mentioned briefly in the Pacific Stock Assessment Report and referred to as the ``Eastern North Pacific Transient'' stock, however,
the Alaska Stock Assessment Report contains assessments of all transient killer whale stocks in the Pacific, and the Alaska Stock Assessment Report
refers to this same stock as the ``West Coast Transient'' stock (Muto et al., 2019).
\7\ The six Mesoplodont beaked whale species off California are M. densirostris, M. carlhubbsi, M. ginkgodens, M. perrini, M. peruvianus, M. stejnegeri.
Notes: na = not available; unk = unknown ; und = undetermined or not provided in the draft 2020 SAR for the Pacific (Carretta et al., 2020) (Carretta et
al., 2019b).
Further, after Navy completed their modeling analysis, the
following species/stocks had zero calculated estimated takes: Bryde's
whale (Eastern Tropical Pacific), Gray whale (Western North Pacific),
Sei whale (Eastern North Pacific), Baird's beaked whale (California,
Oregon, and Washington), Bottlenose dolphin (California Coastal),
Cuvier's beaked whale (California, Oregon, and Washington), Harbor
Porpoise (Morro Bay), Killer whale (Eastern North Pacific Offshore,
Eastern North Pacific Transient or West Coast Transient), Mesoplodont
spp. (California, Oregon, and Washington), Short-finned pilot whale
(California, Oregon, and Washington), and Northern fur seal
(California). NMFS agrees with the Navy's analysis; therefore, these
species are excluded from further analysis.
Below, we include additional information about the marine mammals
in the area of the Specified Activities that informs our analysis, such
as identifying known areas of important habitat or behaviors, or where
Unusual Mortality Events (UME) have been designated.
Critical Habitat
The statutory definition of occupied critical habitat refers to
``physical or biological features essential to the conservation of the
species,'' but the ESA does not specifically define or further describe
these features. ESA-implementing regulations at 50 CFR 424.02 (as
amended, 84 FR 45020; August 27, 2019), however, define such features
as follows: The features that occur in specific areas and that are
essential to support the life-history needs of the species, including
but not limited to, water characteristics, soil type, geological
features, sites, prey, vegetation, symbiotic species, or other
features. A feature may be a single habitat characteristic, or a more
complex combination of habitat characteristics. Features may include
habitat characteristics that support ephemeral or dynamic habitat
conditions. Features may also be expressed in terms relating to
principles of conservation biology, such as patch size, distribution
distances, and connectivity.
On April 21, 2021, NMFS issued a final rule to designate critical
habitat in nearshore waters of the North Pacific Ocean for the
endangered Central America DPS and the threatened Mexico DPS of
humpback whales (86 FR 21082). Critical habitat for the Central America
DPS and Mexico DPS was established within the California Current
Ecosystem (CCE) off the coasts of California, Oregon, and Washington,
representing areas of key foraging habitat. Prey of sufficient quality,
abundance, and accessibility within humpback whale feeding areas to
support feeding and population growth is identified an essential
feature to the conservation of these whales. Because humpback whales
only rarely feed on breeding grounds and during migrations, humpback
whales must have access to adequate prey resources within their feeding
areas to build up their fat stores and meet the nutritional and energy
demands associated with individual survival, growth, reproduction,
lactation, seasonal migrations, and other normal life functions. Given
that each of three humpback whale DPSs very clearly rely on the feeding
areas while within U.S. waters, prey has been identified as a
biological feature that is essential to the conservation of the whales.
The prey essential feature was specifically defined as follows: Prey
species, primarily euphausiids and small pelagic schooling fishes of
[[Page 37802]]
sufficient quality, abundance, and accessibility within humpback whale
feeding areas to support feeding and population growth.
NMFS considered 19 units of habitat as critical habitat for the
listed humpback whale DPSs. There is overlap between the PMSR Study
Area and portions of the habitat designated Units 17 and 18 (see Figure
3.7-5 of the 2020 PMSR DEIS/OEIS) in the final critical habitat rule
(86 FR 21082), which are described below.
Unit 17, referred to as the ``Central California Coast Area,''
extends from 36[deg]00' N to a southern boundary at 34[deg]30' N. The
nearshore boundary is defined by the 30-m isobath, and the seaward
boundary is drawn along the 3,700-m isobath. This unit includes waters
off of southern Monterey County, and San Luis Obispo and Santa Barbara
Counties. Unit 17 covers 6,697 nmi\2\ of marine habitat. This unit
encompasses Morro Bay to Point Sal Biologically Important Area (BIA;
see next section) and typically supports high density feeding
aggregations of humpback whales from April to November (Calambokidis et
al. 2015). Based on acoustic survey data collected during 2004-2009,
large krill hotspots, ranging from 700 km\2\ to 2,100 km\2\, occur off
Big Sur, San Luis Obispo, and Point Sal (Santora et al. 2011). Hotspots
with persistent, heightened abundance of krill were also reported in
this unit in association with bathymetric submarine canyons (Santora et
al. 2018). This is the northernmost portion of humpback whale critical
habitat that overlaps with the PMSR Study Area.
Unit 18, referred to as the ``Channel Islands Area,'' extends from
a northern boundary at 34[deg]30' N to a boundary line that extends
from Oxnard, CA seaward to the 3,700-m isobath, along which the
offshore boundary is drawn. The 50-m isobath forms the shoreward
boundary. This unit includes waters off of Santa Barbara and Ventura
counties. This unit covers 9,799 nmi\2\ of marine habitat. This unit
encompasses the Santa Barbara Channel-San Miguel BIA, which supports
high density feeding aggregations of humpback whales during March
through September (Calambokidis et al. 2015). Based on acoustic survey
data collected during 2004-2009, a krill hotspot of about 780 km\2\ has
been documented off Point Conception (Santora et al. 2011). Some
additional krill hotspots have also been observed in this unit in
association with bathymetric submarine canyons (Santora et al. 2018).
Coastal waters managed by the Navy, as addressed within the Point Mugu
Integrated Natural Resources Management Plan (INRMP) and SNI INRMP, are
not included in the proposed designation as these areas were determined
by NMFS to be ineligible for designation as critical habitat under
section 4(a)(3)(B)(i) of the ESA (84 FR 54354; October 9, 2019).The
Navy does not anticipate national security impacts resulting from
critical habitat designation in the portion of Region/Unit 18 that
overlaps with the PMSR Study Area.
Biologically Important Areas
Biologically Important Areas (BIAs) include areas of known
importance for reproduction, feeding, or migration, or areas where
small and resident populations are known to occur (Van Parijs, 2015).
Unlike ESA critical habitat, these areas are not formally designated
pursuant to any statute or law, but are a compilation of the best
available science intended to inform impact and mitigation analyses. An
interactive map of the BIAs may be found here: <a href="https://cetsound.noaa.gov/biologically-important-area-map">https://cetsound.noaa.gov/biologically-important-area-map</a>.
BIAs off the West Coast of the continental United States with the
potential to overlap portions of the PMSR Study Area include the
following feeding and migration areas for blue whales, gray whales, and
humpback whales and are described in further detail below (Calambokidis
et al., 2015).
Blue Whale Feeding BIAs
Three blue whale feeding BIAs overlap with the PMSR Study Area (see
Figure 3.7-2 of the 2020 PMSR DEIS/OEIS). The Point Conception/Arguello
to Point Sal Feeding Area and Santa Barbara Channel and San Miguel
Feeding Area have large portions within the PMSR Study Area, 87 and 61
percent respectively. The San Nicolas Island Feeding Area is entirely
within the PMSR Study Area (Calambokidis et al., 2015a). Feeding by
blue whales occurs from June through October in these BIAs
(Calambokidis et al., 2015a).
Gray Whale Migration BIAs
Four gray whale migration BIAs overlap with the PMSR Study Area
(see Figure 3.7-3 of the 2020 PMSR DEIS/OEIS). The northward migration
of the Eastern North Pacific stock of gray whales to the feeding
grounds in Arctic waters, Alaska, the Pacific Northwest, and Northern
California occurs in two phases: Northbound Phase A and Northbound
Phase B (Calambokidis et al., 2015). Northbound Phase A migration BIA
consists mainly of adults and juveniles that lead the beginning of the
north-bound migration from late January through July, peaking in April
through July. Newly pregnant females go first to maximize feeding time,
followed by adult females and males, and then juveniles (Jones and
Swartz, 2009). The Northbound Phase B migration BIA consists primarily
of cow-calf pairs that begin their northward migration later (March
through July), as they remain on the reproductive grounds longer to
allow calves to strengthen and rapidly increase in size before the
northward migration (Jones and Swartz, 2009; Urban-Ramirez et al.,
2003). The Potential presence migration BIA (January through July;
October through December) and the Southbound--All migration BIA
(October through March) routes pass through the waters of the PMSR
Study Area.
Humpback Whale Feeding BIAs
Two humpback whale feeding areas overlap with the PMSR Study Area
(Calambokidis et al., 2015) (see Figure 3.7-4 of the 2020 PMSR DEIS/
OEIS). These BIAs include the Morro Bay to Point Sal feeding area
(April through November) and the Santa Barbara Channel-San Miguel
feeding area (March through September) (Calambokidis et al., 2015). The
majority of these BIAs overlap with the PMSR Study Area (approximately
75 percent).
National Marine Sanctuaries
Under Title III of the Marine Protection, Research, and Sanctuaries
Act of 1972 (also known as the National Marine Sanctuaries Act (NMSA)),
NOAA can establish as national marine sanctuaries (NMS), areas of the
marine environment with special conservation, recreational, ecological,
historical, cultural, archaeological, scientific, educational, or
aesthetic qualities. Sanctuary regulations prohibit or regulate
activities that could destroy, cause the loss of, or injure sanctuary
resources pursuant to the regulations for that sanctuary and other
applicable law (15 CFR part 922). NMSs are managed on a site-specific
basis, and each sanctuary has site-specific regulations. Most, but not
all, sanctuaries have site-specific regulatory exemptions from the
prohibitions for certain military activities. Separately, section
304(d) of the NMSA requires Federal agencies to consult with the Office
of National Marine Sanctuaries whenever their activities are likely to
destroy, cause the loss of, or injure a sanctuary resource.
There are two NMSs managed by the Office of National Marine
Sanctuaries within the PMSR Study Area: The Channel Islands NMS and a
small portion of the Monterey Bay NMS. The
[[Page 37803]]
Channel Islands NMS is an ecosystem-based managed sanctuary consisting
of an area of 1,109 nmi\2\ around Anacapa Island, Santa Cruz Island,
Santa Rosa Island, San Miguel Island, and Santa Barbara Island to the
south. It encompasses sensitive habitats (e.g., kelp forest habitat,
deep benthic habitat) and includes various shipwrecks and maritime
heritage artifacts. The Channel Islands NMS waters and its remote,
isolated position at the confluence of two major ocean currents support
significant biodiversity of marine mammals, fish, and invertebrates. At
least 33 species of cetaceans have been reported in the Channel Islands
NMFS region with common species, including: Long-beaked common dolphin,
short-beaked common dolphin, Bottlenose dolphin, Pacific white-sided
dolphin, Northern right whale dolphin, Risso's dolphin, California gray
whale, Blue whale, and Humpback whale. The three species of pinnipeds
that are commonly found throughout or in part of the Channel Islands
NMS include: California sea lion, Northern elephant seal, and Pacific
harbor seal. About 877 nmi\2\, or 79 percent of the Channel Island NMS,
occurs within the PMSR Study Area (see Chapter 6 of the 2020 PMSR DEIS/
OEIS and Figure 6.1-1). The Monterey Bay NMS is an ecosystem-based
managed sanctuary consisting of an area of 4,601 nmi\2\ stretching from
Marin to Cambria and extending an average of 30 miles from shore. The
Monterey Bay NMS contains extensive kelp forests and one of North
America's largest underwater canyons and closest-to-shore deep ocean
environments. Its diverse marine ecosystem also includes rugged rocky
shores, wave-swept sandy beaches and tranquil estuaries. These habitats
support a variety of marine life, including 36 species of marine
mammals, more than 180 species of seabirds and shorebirds, at least 525
species of fishes, and an abundance of invertebrates and algae. Of the
36 species of marine mammals, six are pinnipeds with California sea
lions being the most common, and the remainder are twenty-six species
of cetaceans. Only 19 nmi\2\, or less than 1 percent of the Monterey
Bay NMS, occurs within the PMSR Study Area (see Chapter 6 of the 2020
PMSR DEIS/OEIS and Figure 6.1-1).
Unusual Mortality Events (UMEs)
An UME is defined under Section 410(6) of the MMPA as a stranding
that is unexpected; it involves a significant die-off of any marine
mammal population, and demands immediate response. From 1991 to the
present, there have been 14 formally recognized UMEs affecting marine
mammals in California and involving species under NMFS' jurisdiction.
Three UMEs with ongoing or recently closed investigations in the PMSR
Study Area that inform our analysis are discussed below. The California
sea lion UME in California was closed on May 6, 2020. The Guadalupe fur
seal UME in California and the gray whale UME along the west coast of
North America are active and involve ongoing investigations.
California Sea Lion UME
From January 2013 through September 2016, a greater than expected
number of young malnourished California sea lions (Zalophus
californianus) stranded along the coast of California. Sea lions
stranding from an early age (6-8 months old) through two years of age
(hereafter referred to as juveniles) were consistently underweight
without other disease processes detected. Of the 8,122 stranded
juveniles attributed to the UME, 93 percent stranded alive (n = 7,587,
with 3,418 of these released after rehabilitation) and 7 percent (n =
531) stranded dead. Several factors are hypothesized to have impacted
the ability of nursing females and young sea lions to acquire adequate
nutrition for successful pup rearing and juvenile growth. In late 2012,
decreased anchovy and sardine recruitment (CalCOFI data, July 2013) may
have led to nutritionally stressed adult females. Biotoxins were
present at various times throughout the UME, and while they were not
detected in the stranded juvenile sea lions (whose stomachs were empty
at the time of stranding), biotoxins may have impacted the adult
females' ability to support their dependent pups by affecting their
cognitive function (e.g., navigation, behavior towards their
offspring). Therefore, the role of biotoxins in this UME, via its
possible impact on adult females' ability to support their pups, is
unclear. The proposed primary cause of the UME was malnutrition of sea
lion pups and yearlings due to ecological factors. These factors
included shifts in distribution, abundance and/or quality of sea lion
prey items around the Channel Island rookeries during critical sea lion
life history events (nursing by adult females, and transitioning from
milk to prey by young sea lions). These prey shifts were most likely
driven by unusual oceanographic conditions at the time due to the event
known as the ``Warm Water Blob'' and El Ni[ntilde]o. This investigation
closed on May 6, 2020. Please refer to: <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2013-2016-california-sea-lion-unusual-mortality-event-california">https://www.fisheries.noaa.gov/national/marine-life-distress/2013-2016-california-sea-lion-unusual-mortality-event-california</a> for more information on this UME.
Guadalupe Fur Seal UME
Increased strandings of Guadalupe fur seals began along the entire
coast of California in January 2015 and were eight times higher than
the historical average (approximately 10 seals/yr). Strandings have
continued since 2015 and remained well above average through 2020.
Numbers by year are as follows: 2015 (98), 2016 (76), 2017 (62), 2018
(45), 2019 (116), 2020 (95 as of December 17, 2020). The total number
of Guadalupe fur seals stranding in California from January 1, 2015,
through December 17, 2020, in the UME is 492. Strandings of Guadalupe
fur seals became elevated in the spring of 2019 in Washington and
Oregon, and strandings for seals in these two states subsequently
(starting from January 1, 2019) have been added to the UME. The current
total number of strandings in Washington and Oregon is 133 seals,
including 91 in 2019 and 42 in 2020 as of December 17, 2020. Strandings
are seasonal and generally peak in April through June of each year. The
Guadalupe fur seal strandings involved the stranding of mostly weaned
pups and juveniles (1-2 years old), with both live and dead strandings
occurring. Current studies of this UME find that the majority of
stranded animals experienced primary malnutrition with secondary
bacterial and parasitic infections. The California portion of this UME
was occurring in the same area where the 2013-2016 California sea lion
UME occurred. This investigation is ongoing. Please refer to: <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2015-2020-guadalupe-fur-seal-unusual-mortality-event-california">https://www.fisheries.noaa.gov/national/marine-life-distress/2015-2020-guadalupe-fur-seal-unusual-mortality-event-california</a> for more
information on this UME.
Gray Whale UME
Since January 1, 2019, elevated levels of gray whale strandings
have occurred along the west coast of North America, from Mexico to
Canada. As of December 17, 2020, there have been a total of 385
strandings along the coasts of the United States, Canada, and Mexico,
with 201 of those strandings occurring along the U.S. coast. Of the
strandings on the U.S. coast, 93 have occurred in Alaska, 47 in
Washington, 9 in Oregon, and 52 in California. Partial necropsy
examinations conducted on a subset of stranded whales have shown
evidence of poor to thin body condition, killer whale predation, and
human
[[Page 37804]]
interactions. As part of the UME investigation process, NOAA is
assembling an independent team of scientists to coordinate with the
Working Group on Marine Mammal UMEs to review the data collected,
sample stranded whales, and determine the next steps for the
investigation. Please refer to: <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2020-gray-whale-unusual-mortality-event-along-west-coast">https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2020-gray-whale-unusual-mortality-event-along-west-coast</a>.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary of the ways that components of the
specified activity may impact marine mammals and their habitat. The
Estimated Take of Marine Mammals section later in this rule includes a
quantitative analysis of the number of instances of take that could
occur from these activities. The Preliminary Analysis and Negligible
Impact Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
Measures section to draw conclusions regarding the likely impacts of
these activities on the reproductive success or survivorship of
individuals and whether those impacts on individuals are likely to
adversely affect the species through effects on annual rates of
recruitment or survival.
The Navy has requested authorization for the take of marine mammals
that may occur incidental to training and testing activities in the
PMSR Study Area. The Navy analyzed potential impacts to marine mammals
from explosive sources, target and missile launches from SNI, and from
vessel use in its rulemaking/LOA application. NMFS carefully reviewed
the information provided by the Navy along with independently reviewing
applicable scientific research and literature and other information to
evaluate the potential effects of the Navy's activities on marine
mammals.
Other potential impacts to marine mammals from training and testing
activities in the PMSR Study Area were analyzed in the 2020 PMSR DEIS/
OEIS, in consultation with NMFS as a cooperating agency. In particular,
the Navy determined that these activities were unlikely to result in
any incidental take from vessel strike or in any serious injury or
mortality from explosive detonations (discussed in this section below),
and the Navy has not requested authorizations of any such incidental
take. NMFS agrees with these determinations by the Navy. Accordingly,
in this proposed rule NMFS' analysis focuses on the potential effects
on marine mammals from the activity components that may cause the take
of marine mammals: Exposure to explosive stressors and launches.
For the purpose of MMPA incidental take authorizations, NMFS'
effects assessments serve four primary purposes: (1) To determine
whether the specified activities would have a negligible impact on the
affected species or stocks of marine mammals (based on whether it is
likely that the activities would adversely affect the species or stocks
through effects on annual rates of recruitment or survival); (2) to
determine whether the specified activities would have an unmitigable
adverse impact on the availability of the species or stocks for
subsistence uses; (3) to prescribe the permissible methods of taking
(i.e., Level B harassment (behavioral disturbance, incurred directly or
as a result of temporary threshold shift (TTS)), and Level A harassment
(permanent threshold shift (PTS) and non-auditory injury)), including
identification of the number and types of take that could occur by
harassment, serious injury, or mortality, and to prescribe other means
of effecting the least practicable adverse impact on the species or
stocks and their habitat (i.e., mitigation measures); and (4) to
prescribe requirements pertaining to monitoring and reporting.
Marine mammals may be affected by Navy activities by sensory
impairment (permanent and temporary threshold shifts and acoustic
masking), physiological responses (particular stress responses), direct
behavioral disturbance, or habitat effects. The Estimated Take of
Marine Mammals section discusses how the potential effects on marine
mammals from the impulsive acoustic sources considered in this rule
relate to the MMPA definitions of Level A harassment and Level B
harassment, and quantifies those effects that rise to the level of a
take. The Preliminary Analysis and Negligible Impact Determination
section assesses whether the proposed authorized take would have a
negligible impact on the affected species and stocks.
Sections 6, 7, and 9 of the Navy's application include summaries of
the ways that components of the specified activity may impact marine
mammals and their habitat, including specific discussion of potential
effects to marine mammals from noise and other stressors produced
through the use explosives detonating at or near the surface and noise
from launch events on SNI. We have reviewed the Navy's discussion of
potential effects for accuracy and completeness in its application and
refer to that information rather than repeating it in full here. Below
we include a summary of the potential effects to marine mammals.
Additionally, NMFS has included a comprehensive discussion of the
potential effects of similar activities on marine mammals, including
specifically from Navy testing and training exercises that use
explosives, in other Federal Register notices. For additional detail,
we refer the reader to these notices; please see, 85 FR 72312 (November
9, 2020) (Navy testing and training, including explosives); 84 FR 28462
(June 12, 2019) (Navy IHA on target and missile launches from SNI); and
79 FR 32678 (June 6, 2014) (Navy previous rule on target and missile
launches from SNI), or view documents available online at
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities">www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities</a>.
Below we provide a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used in this
proposal, as well as a brief overview of the potential effects to
marine mammals associated with the Navy's proposed activities. The
proposed training and testing exercises have the potential to cause
take of marine mammals by exposing them to impulsive noise and pressure
waves generated by explosive detonation at or near the surface of the
water as well as by impulsive noise target and missile launches from
SNI. Exposure to noise or pressure resulting from these detonations and
launches could result in non-lethal injury (Level A harassment) or
disturbance (Level B harassment). The potential effects of impulsive
sound and pressure from the proposed training and testing activities
may include one or more of the following: Tolerance, masking,
disturbance, hearing threshold shift, and stress responses. In
addition, NMFS also considered the potential for harassment from
vessels and serious injury and mortality from explosive detonations.
Description of Sound Sources
This section contains a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used in this
proposal inasmuch as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document. For general
information on sound and its interaction with the marine environment,
please see, e.g., Au and
[[Page 37805]]
Hastings (2008); Richardson et al. (1995); Urick (1983).
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz or cycles per second. Wavelength is the distance
between two peaks or corresponding points of a sound wave (length of
one cycle). Higher frequency sounds have shorter wavelengths than lower
frequency sounds, and typically attenuate (decrease) more rapidly,
except in certain cases in shallower water. Amplitude is the height of
the sound pressure wave or the ``loudness'' of a sound and is typically
described using the relative unit of the decibel (dB). A sound pressure
level (SPL) in dB is described as the ratio between a measured pressure
and a reference pressure (for underwater sound, this is 1 microPascal
([mu]Pa)), and is a logarithmic unit that accounts for large variations
in amplitude. Therefore, a relatively small change in dB corresponds to
large changes in sound pressure. The source level (SL) represents the
SPL referenced at a distance of 1 m from the source (referenced to 1
[mu]Pa), while the received level is the SPL at the listener's position
(referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they may be accounted for in the summation of
pressure levels (Hastings and Popper, 2005). This measurement is often
used in the context of discussing behavioral effects, in part because
behavioral effects, which often result from auditory cues, may be
better expressed through averaged units than by peak pressures.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy in a stated frequency band over a stated
time interval or event and considers both intensity and duration of
exposure. The per-pulse SEL is calculated over the time window
containing the entire pulse (i.e., 100 percent of the acoustic energy).
SEL is a cumulative metric; it can be accumulated over a single pulse,
or calculated over periods containing multiple pulses. Cumulative SEL
represents the total energy accumulated by a receiver over a defined
time window or during an event. Peak sound pressure (also referred to
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous
sound pressure measurable in the water at a specified distance from the
source and is represented in the same units as the rms sound pressure.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for sound produced by the
pile driving activity considered here. The compressions and
decompressions associated with sound waves are detected as changes in
pressure by aquatic life and man-made sound receptors such as
hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound, which is
defined as environmental background sound levels lacking a single
source or point (Richardson et al., 1995). The sound level of a region
is defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., wind and
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
(e.g., vessels, dredging, construction) sound. A number of sources
contribute to ambient sound, including wind and waves, which are a main
source of naturally occurring ambient sound for frequencies between 200
Hz and 50 kHz (Mitson, 1995). In general, ambient sound levels tend to
increase with increasing wind speed and wave height. Precipitation can
become an important component of total sound at frequencies above 500
Hz, and possibly down to 100 Hz during quiet times. Marine mammals can
contribute significantly to ambient sound levels, as can some fish and
snapping shrimp. The frequency band for biological contributions is
from approximately 12 Hz to over 100 kHz. Sources of ambient sound
related to human activity include transportation (surface vessels),
dredging and construction, oil and gas drilling and production,
geophysical surveys, sonar, and explosions. Vessel noise typically
dominates the total ambient sound for frequencies between 20 and 300
Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels are created, they attenuate
rapidly. The sum of the various natural and anthropogenic sound sources
that comprise ambient sound at any given location and time depends not
only on the source levels (as determined by current weather conditions
and levels of biological and human activity) but also on the ability of
sound to propagate through the environment. In turn, sound propagation
is dependent on the spatially and temporally varying properties of the
water column and sea floor, and is frequency-dependent. As a result of
the dependence on a large number of varying factors, ambient sound
levels can be expected to vary widely over both coarse and fine spatial
and temporal scales. Sound levels at a given frequency and location can
vary by 10-20 decibels (dB) from day to day (Richardson et al., 1995).
The result is that, depending on the source type and its intensity,
sound from the specified activity may be a negligible addition to the
local environment or could form a distinctive signal that may affect
marine mammals. Details of source types are described in the following
text.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al. (2007) and NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
Underwater Thresholds for Onset of Permanent and Temporary Threshold
Shift (Acoustic Technical Guidance) (NMFS, 2018) for an in-depth
discussion of these concepts. The distinction between these two sound
types is not always obvious, as certain signals share properties of
both pulsed and non-pulsed sounds. A signal near a source could be
categorized as a pulse, but due to propagation effects as it moves
farther from the source, the signal duration becomes longer (e.g.,
Greene and Richardson, 1988).
Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing,
[[Page 37806]]
oscillating maximal and minimal pressures, and generally have an
increased capacity to induce physical injury as compared with sounds
that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or intermittent (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems. The
duration of such sounds, as received at a distance, can be greatly
extended in a highly reverberant environment.
Serious Injury or Mortality From Explosive Detonations
Serious injury or mortality to marine mammals from explosive
detonations would consist of primary blast injury, which refers to
those injuries that result from the compression of a body exposed to a
blast wave and is usually observed as barotrauma of gas-containing
structures (e.g., lung and gut) and structural damage to the auditory
system (Greaves et al., 1943; Office of the Surgeon General, 1991;
Richmond et al., 1973). The near instantaneous high magnitude pressure
change near an explosion can injure an animal where tissue material
properties significantly differ from the surrounding environment, such
as around air-filled cavities in the lungs or gastrointestinal (GI)
tract. The gas-containing organs (lungs and GI tract) are most
vulnerable to primary blast injury. Severe injuries to these organs are
presumed to result in mortality (e.g., severe lung damage may introduce
air into the cardiopulmonary vascular system, resulting in lethal air
emboli). Large pressure changes at tissue-air interfaces in the lungs
and GI tract may cause tissue rupture, resulting in a range of injuries
depending on degree of exposure. Recoverable injuries would include
slight lung injury, such as capillary interstitial bleeding, and
contusions to the GI tract. More severe injuries, such as tissue
lacerations, major hemorrhage, organ rupture, or air in the chest
cavity (pneumothorax), would significantly reduce fitness and likely
cause death in the wild. Rupture of the lung may also introduce air
into the vascular system, producing air emboli that can cause a stroke
or heart attack by restricting oxygen delivery to critical organs.
Susceptibility would increase with depth, until normal lung collapse
(due to increasing hydrostatic pressure) and increasing ambient
pressures again reduce susceptibility.
The Navy performed a quantitative analysis (refer to the Navy's
Acoustic Effects Model section) to estimate the probability that marine
mammals could be exposed to the sound and energy from explosions during
Navy testing and training activities and the effects of those
exposures. The effects of underwater explosions on marine mammals
depend on a variety of factors including animal size and depth; charge
size and depth; depth of the water column; and distance between the
animal and the charge. In general, an animal would be less susceptible
to injury near the water surface because the pressure wave reflected
from the water surface would interfere with the direct path pressure
wave, reducing positive pressure exposure. There are no explosives
detonated underwater for the proposed activities, and those that
detonate at or near the surface of the water are unlikely to transfer
energy underwater sufficient to result in non-auditory injury (GI
injury or lung injury) or mortality. NMFS agrees with the Navy's
analysis that no mortality or serious injury from tissue damage in the
form of GI injury or lung injury is anticipated to result from the
proposed activities. The Navy did not request and NMFS does not propose
it for authorization or discuss further. For additional details on the
criteria for estimating non-auditory physiological impacts on marine
mammals due to naval underwater explosions, we refer the reader to the
report, Criteria and Thresholds for U.S. Navy Acoustic and Explosive
Effects Analysis (Phase III) (U.S. Department of the Navy, 2017e).
Hearing Loss--Threshold Shift
Marine mammals exposed to high-intensity sound, or to lower-
intensity sound for prolonged periods, can experience hearing threshold
shift, which is the loss of hearing sensitivity at certain frequency
ranges after cessation of sound (Finneran, 2015). Threshold shift can
be permanent (PTS), in which case the loss of hearing sensitivity is
not fully recoverable, or temporary (TTS), in which case the animal's
hearing threshold would recover over time (Southall et al., 2007).
Irreparable damage to the inner or outer cochlear hair cells may cause
PTS; however, other mechanisms are also involved, such as exceeding the
elastic limits of certain tissues and membranes in the middle and inner
ears and resultant changes in the chemical composition of the inner ear
fluids (Southall et al., 2007). PTS is considered an injury and Level A
harassment while TTS is considered to be Level B harassment and not
considered an injury.
Hearing loss, or threshold shift (TS), is typically quantified in
terms of the amount (in decibels [dB]) that hearing thresholds at one
or more specified frequencies are elevated, compared to their pre-
exposure values, at some specific time after the noise exposure. The
amount of TS measured usually decreases with increasing recovery time--
the amount of time that has elapsed since a noise exposure. If the TS
eventually returns to zero (i.e., the hearing threshold returns to the
pre-exposure value), the threshold shift is called a TTS. If the TS
does not completely recover (the threshold remains elevated compared to
the pre-exposure value), the remaining TS is a PTS.
Hearing loss has only been studied in a few species of marine
mammals, although hearing studies with terrestrial mammals are also
informative. There are no direct measurements of hearing loss in marine
mammals due to exposure to explosive sources. The sound resulting from
an explosive detonation is considered an impulsive sound and shares
important qualities (i.e., short duration and fast rise time) with
other impulsive sounds such as those produced by air guns. General
research findings regarding TTS and PTS in marine mammals, as well as
findings specific to exposure to other impulsive sound sources, are
discussed in Section 6.4.1.2, (Loss of Hearing Sensitivity and Auditory
Injury) of the Navy's application.
Marine mammal TTS data from impulsive sources are limited to two
studies with measured TTS of 6 dB or more: Finneran et al. (2002)
reported behaviorally measured TTSs of 6 and 7 dB in a beluga exposed
to single impulses from a seismic water gun, and Lucke et al. (2009)
reported Audio-evoked Potential measured TTS of 7-20 dB in a harbor
porpoise exposed to single impulses from a seismic air gun.
In addition to these data, Kastelein et al. (2015a) reported
behaviorally measured mean TTS of 4 dB at 8 kHz and 2 dB at 4 kHz after
a harbor porpoise was exposed to a series of impulsive sounds produced
by broadcasting underwater recordings of impact pile driving strikes
through underwater sound projectors. The cumulative SEL was
approximately 180 decibels referenced to 1 micropascal squared seconds
(dB re 1 [mu]Pa\2\s). The pressure waveforms for the simulated pile
strikes exhibited significant
[[Page 37807]]
``ringing'' not present in the original recordings, and most of the
energy in the broadcasts was between 500 and 800 Hz. As a result, some
questions exist regarding whether the fatiguing signals were
representative of underwater pressure signatures from impact pile
driving.
Several impulsive noise exposure studies have also been conducted
without behaviorally measurable TTS. Specifically, Finneran et al.
(2000) exposed dolphins and belugas to single impulses from an
``explosion simulator,'' and Finneran et al. (2015) exposed three
dolphins to sequences of 10 impulses from a seismic air gun (maximum
cumulative SEL = 193-195 dB re 1 [mu]Pa\2\s, peak SPL = 196-210 dB re 1
[mu]Pa) without measurable TTS. Finneran et al. (2003) exposed two sea
lions to single impulses from an arc-gap transducer with no measurable
TTS (maximum unweighted SEL = 163 dB re 1 [mu]Pa\2\s, peak SPL = 183 dB
re 1 [mu]Pa).
Numerous studies have directly examined noise-induced hearing loss
in marine mammals from non-impulsive sources (see Finneran, 2015). In
these studies, hearing thresholds were measured in marine mammals
before and after exposure to intense sounds. The difference between the
pre-exposure and post-exposure thresholds was then used to determine
the amount of TTS at various post-exposure times. The major findings
from these studies, which include the following, highlight general
concepts that are thought to be applicable across all types of sounds:
<bullet> The amount of TTS varies with the hearing test frequency.
As the exposure SPL increases, the frequency at which the maximum TTS
occurs also increases (Kastelein et al., 2014b). For high-level
exposures, the maximum TTS typically occurs one-half to one octave
above the exposure frequency (Finneran et al., 2007; Mooney et al.,
2009a; Nachtigall et al., 2004; Popov et al., 2011; Popov et al., 2013;
Schlundt et al., 2000). The overall spread of TTS from tonal exposures
can therefore extend over a large frequency range (i.e., narrowband
exposures can produce broadband [greater than one octave] TTS).
<bullet> The amount of TTS increases with exposure SPL and duration
and is correlated with sound exposure level (SEL), especially if the
range of exposure durations is relatively small (Kastak et al., 2007;
Kastelein et al., 2014b; Popov et al., 2014). As the exposure duration
increases, however, the relationship between TTS and SEL begins to
break down. Specifically, duration has a more significant effect on TTS
than would be predicted on the basis of SEL alone (Finneran et al.,
2010a, 2010b; Kastak et al., 2005; Mooney et al., 2009a). This means if
two exposures have the same SEL but different durations, the exposure
with the longer duration (thus lower SPL) will tend to produce more TTS
than the exposure with the higher SPL and shorter duration. In most
acoustic impact assessments, the scenarios of interest involve shorter
duration exposures than the marine mammal experimental data from which
impact thresholds are derived; therefore, use of SEL tends to
overestimate the amount of TTS. Despite this, SEL continues to be used
in many situations because it is relatively simple, more accurate than
SPL alone, and lends itself easily to scenarios involving multiple
exposures with different SPL.
<bullet> The amount of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity,
are less hazardous than those at higher frequencies, near the region of
best sensitivity (Finneran and Schlundt, 2013). The onset of TTS--
defined as the exposure level necessary to produce 6 dB of TTS (i.e.,
clearly above the typical variation in threshold measurements)--also
varies with exposure frequency. At low frequencies onset-TTS exposure
levels are higher compared to those in the region of best sensitivity.
<bullet> TTS can accumulate across multiple exposures, but the
resulting TTS will be less than the TTS from a single, continuous
exposure with the same SEL (Finneran et al., 2010a; Kastelein et al.,
2014a; Kastelein et al., 2015b; Mooney et al., 2009b). 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.
<bullet> The amount of observed TTS tends to decrease with
increasing time following the exposure; however, the relationship is
not monotonic (i.e., increasing exposure does not always increase TTS).
The time required for complete recovery of hearing depends on the
magnitude of the initial shift; for relatively small shifts recovery
may be complete in a few minutes, while large shifts (e.g., ~40 dB) may
require several days for recovery. Under many circumstances TTS
recovers linearly with the logarithm of time (Finneran et al., 2010a,
2010b; Finneran and Schlundt, 2013; Kastelein et al., 2012a; Kastelein
et al., 2012b; Kastelein et al., 2013a; Kastelein et al., 2014a, 2014b;
Kastelein et al., 2014c; Popov et al., 2011; Popov et al., 2013; Popov
et al., 2014). This means that for each doubling of recovery time, the
amount of TTS will decrease by the same amount (e.g., 6 dB recovery per
doubling of time).
The proposed activities include both TTS and a limited amount of
PTS on some marine mammals.
Hearing Loss from SNI Target and Missile Launches--Missile launches
are characterized by sudden onset of sound, moderate to high peak sound
levels (depending on the type of missile and distance), and short sound
duration. Although it is possible that some pinnipeds may incur TTS
during launches from SNI, hearing impairment has not been measured for
pinniped species exposed to launch sounds. Auditory brainstem response
(i.e., hearing assessment using measurements of electrical responses of
the brain) was used to demonstrate that harbor seals did not exhibit
loss in hearing sensitivity following launches of large rockets at
Vandenberg Air Force Base (VAFB) (Thorson et al., 1999; Thorson et al.,
1998). However, the hearing tests did not begin until at least 45
minutes after the launch; therefore, harbor seals may have incurred TTS
which was undetectable by the time testing was begun. There was no sign
of PTS in any of the harbor seals tested (Thorson et al., 1999; Thorson
et al., 1998). Since 2001, no launch events at SNI have exposed
pinnipeds to noise levels at or exceeding those where PTS could be
incurred.
Based on measurements of received sound levels during previous
launches at SNI (Burke 2017; Holst et al., 2010; Holst et al., 2005a;
Holst et al., 2008; Holst et al., 2011; Ugoretz 2016; Ugoretz and
Greene Jr. 2012), the Navy expects that there is a very limited
potential of TTS for a few of the pinnipeds present, particularly for
phocids. Available evidence from launch monitoring at SNI in 2001-2017
suggests that only a small number of launch events produced sound
levels that could elicit TTS for some pinnipeds (Burke 2017; Holst et
al., 2008; Holst et al., 2011; Ugoretz 2016; Ugoretz and Greene Jr.
2012). In general, if any TTS were to occur to pinnipeds, it is
expected to be mild and reversible. It is possible that some launch
sounds as measured close to the launchers may exceed the permanent
threshold shift (PTS) criteria, but it is not expected that any
pinnipeds would be close enough to the launchers to be exposed to
sounds strong enough to cause PTS. Due to the expected sound levels of
the activities proposed and the distance of the activity from marine
mammal habitat, the effects of sounds from the proposed activities are
unlikely to result in PTS.
[[Page 37808]]
Physiological Stress
There is growing interest in monitoring and assessing the impacts
of stress responses to sound in marine animals. Classic stress
responses begin when an animal's central nervous system perceives a
potential threat to its homeostasis. That perception triggers stress
responses regardless of whether a stimulus actually threatens the
animal; the mere perception of a threat is sufficient to trigger a
stress response (Moberg, 2000; Sapolsky et al., 2005; Seyle, 1950).
Once an animal's central nervous system perceives a threat, it mounts a
biological response or defense that consists of a combination of the
four general biological defense responses: behavioral responses,
autonomic nervous system responses, neuroendocrine responses, or immune
responses.
According to Moberg (2000), in the case of many stressors, an
animal's first and sometimes most economical (in terms of biotic costs)
response is behavioral avoidance of the potential stressor or avoidance
of continued exposure to a stressor. An animal's second line of defense
to stressors involves the sympathetic part of the autonomic nervous
system and the classical ``fight or flight'' response which includes
the cardiovascular system, the gastrointestinal system, the exocrine
glands, and the adrenal medulla to produce changes in heart rate, blood
pressure, and gastrointestinal activity that humans commonly associate
with ``stress.'' These responses have a relatively short duration and
may or may not have significant long-term effect on an animal's
welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems or sympathetic nervous systems; the system that
has received the most study has been the hypothalmus-pituitary-adrenal
system (also known as the HPA axis in mammals or the hypothalamus-
pituitary-interrenal axis in fish and some reptiles). Unlike stress
responses associated with the autonomic nervous system, virtually all
neuro-endocrine 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 (Moberg,
1987; Rivier and Rivest, 1991), altered metabolism (Elasser et al.,
2000), reduced immune competence (Blecha, 2000), and behavioral
disturbance (Moberg, 1987; Blecha, 2000). Increases in the circulation
of glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
Because there are many unknowns regarding the occurrence of
acoustically induced stress responses in marine mammals, it is assumed
that any physiological response (e.g., hearing loss or injury) or
significant behavioral response is also associated with a stress
response.
Auditory Masking
Sound can disrupt behavior through masking, or interfering with, an
animal's ability to detect, recognize, or discriminate between acoustic
signals of interest (e.g., those used for intraspecific communication
and social interactions, prey detection, predator avoidance, or
navigation) (Richardson et al., 1995; Erbe and Farmer, 2000; Tyack,
2000; Erbe et al., 2016). Masking occurs when the receipt of a sound is
interfered with by another coincident sound at similar frequencies and
at similar or higher intensity, and may occur whether the sound is
natural (e.g., snapping shrimp, wind, waves, precipitation) or
anthropogenic (e.g., shipping, sonar, seismic exploration) in origin.
As described in detail in the 2020 PMSR DSEIS/OEIS, 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. Masking these
acoustic signals can disturb the behavior of individual animals, groups
of animals, or entire populations. Masking can lead to behavioral
changes including vocal changes (e.g., Lombard effect, increasing
amplitude, or changing frequency), cessation of foraging, and leaving
an area, to both signalers and receivers, in an attempt to compensate
for noise levels (Erbe et al., 2016). Masking only occurs in the
presence of the masking noise and does not persist after the cessation
of the noise. Masking may lead to a change in vocalizations or a change
in behavior (e.g., cessation of foraging, leaving an area). There are
no direct observations of masking in marine mammals due to exposure to
sound from explosive detonations or launches and nor would they be
predicted given the shorter duration of these sounds.
Behavioral Disturbance
Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception
of and response to (nature and magnitude) an acoustic event. An
animal's prior experience with a sound or sound source affects whether
it is less likely (habituation) or more likely (sensitization) to
respond to certain sounds in the future (animals can also be innately
predisposed to respond to certain sounds in certain ways) (Southall et
al., 2007). Related to the sound itself, the perceived nearness of the
sound, bearing of the sound (approaching vs. retreating), the
similarity of a sound to biologically relevant sounds in the animal's
environment (i.e., calls of predators, prey, or conspecifics), and
familiarity of the sound may affect the way an animal responds to the
sound (Southall et al., 2007, DeRuiter et al., 2013). Individuals (of
different age, gender, reproductive status, etc.) among most
populations will have variable hearing capabilities, and differing
behavioral sensitivities to sounds that will be affected by prior
conditioning, experience, and current activities of those individuals.
Often, specific acoustic features of the sound and contextual variables
(i.e., proximity, duration, or recurrence of the sound or the current
behavior that the marine mammal is engaged in or its prior experience),
as well as entirely separate factors such as the physical presence of a
nearby vessel, may be more relevant to the animal's response than the
received level alone.
Controlled experiments with captive marine mammals have shown
pronounced behavioral reactions, including avoidance of loud underwater
sound sources (Ridgway et al., 1997; Finneran et al., 2003). These may
be of limited relevance to the proposed activities given that airborne
sound, and not underwater sound, may result in harassment of marine
mammals as a result of the proposed activities; however we present this
information as background on the potential impacts of sound on marine
mammals. Observed responses of wild marine mammals to loud pulsed sound
sources (typically seismic guns or acoustic harassment devices) have
been varied but often consist of avoidance behavior or other behavioral
changes suggesting discomfort (Morton and Symonds, 2002; Thorson and
Reyff, 2006; see also Gordon et al., 2004; Wartzok et al., 2003;
Nowacek et al., 2007).
The onset of noise can result in temporary, short-term changes in
an animal's typical behavior and/or
[[Page 37809]]
avoidance of the affected area. These behavioral changes may include:
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior; avoidance of areas where sound sources
are located; and/or flight responses (Richardson et al., 1995).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could potentially be biologically significant if the
change affects growth, survival, or reproduction. The onset of
behavioral disturbance from anthropogenic sound depends on both
external factors (characteristics of sound sources and their paths) and
the specific characteristics of the receiving animals (hearing,
motivation, experience, demography) and is difficult to predict
(Southall et al., 2007).
Ellison et al. (2012) outlined an approach to assessing the effects
of sound on marine mammals that incorporates contextual-based factors.
The authors recommend considering not just the received level of sound,
but also the activity the animal is engaged in at the time the sound is
received, the nature and novelty of the sound (i.e., is this a new
sound from the animal's perspective), and the distance between the
sound source and the animal. They submit that this ``exposure
context,'' as described, greatly influences the type of behavioral
response exhibited by the animal. Forney et al. (2017) also point out
that an apparent lack of response (e.g., no displacement or avoidance
of a sound source) may not necessarily mean there is no cost to the
individual or population, as some resources or habitats may be of such
high value that animals may choose to stay, even when experiencing
stress or hearing loss. Forney et al. (2017) recommend considering both
the costs of remaining in an area of noise exposure such as TTS, PTS,
or masking, which could lead to an increased risk of predation or other
threats or a decreased capability to forage, and the costs of
displacement, including potential increased risk of vessel strike,
increased risks of predation or competition for resources, or decreased
habitat suitable for foraging, resting, or socializing. This sort of
contextual information is challenging to predict with accuracy for
ongoing activities that occur over large spatial and temporal expanses.
However, distance is one contextual factor for which data exist to
quantitatively inform a take estimate, and the method for predicting
Level B harassment in this proposed rule does consider distance to the
source. Other factors are often considered qualitatively in the
analysis of the likely consequences of sound exposure, where supporting
information is available.
Exposure of marine mammals to sound sources can result in, but is
not limited to, no response or any of the following observable
responses: Increased alertness; orientation or attraction to a sound
source; vocal modifications; cessation of feeding; cessation of social
interaction; alteration of movement or diving behavior; habitat
abandonment (temporary or permanent); and, in severe cases, panic,
flight, stampede, or stranding, potentially resulting in death
(Southall et al., 2007). A review of marine mammal responses to
anthropogenic sound was first conducted by Richardson (1995). More
recent reviews (Nowacek et al., 2007; DeRuiter et al., 2012 and 2013;
Ellison et al., 2012; Gomez et al., 2016) address studies conducted
since 1995 and focused on observations where the received sound level
of the exposed marine mammal(s) was known or could be estimated. Gomez
et al. (2016) conducted a review of the literature considering the
contextual information of exposure in addition to received level and
found that higher received levels were not always associated with more
severe behavioral responses and vice versa. Southall et al. (2016)
states that results demonstrate that some individuals of different
species display clear yet varied responses, some of which have negative
implications, while others appear to tolerate high levels, and that
responses may not be fully predictable with simple acoustic exposure
metrics (e.g., received sound level). Rather, the authors state that
differences among species and individuals along with contextual aspects
of exposure (e.g., behavioral state) appear to affect response
probability.
During an activity with a series of explosions (not concurrent
multiple explosions shown in a burst), an animal is expected to exhibit
a startle reaction to the sound of the first detonation followed by
another behavioral response after multiple detonations. At close ranges
and high sound levels, avoidance of the area around the explosions is
the assumed behavioral response in most cases. In certain
circumstances, exposure to loud sounds can interrupt feeding behaviors
and potentially decrease foraging success, interfere with communication
or migration, or disrupt important reproductive or young-rearing
behaviors, among other effects.
Behavioral Disturbance from SNI Target and Missile Launches--
Pinnipeds may be exposed to airborne sounds that have the potential to
result in behavioral harassment, depending on an animal's distance from
the sound and the type of missile being launched. Sound could cause
hauled out pinnipeds to exhibit changes in their normal behavior, such
as temporarily abandoning their habitat.
Responses of pinnipeds on beaches exposed to acoustic disturbance
arising from launches are highly variable. Harbor seals can be more
reactive when hauled out compared to other species, such as northern
elephant seals. Northern elephant seals generally exhibit no reaction
at all, except perhaps a heads-up response or some stirring. If
northern elephant seals do react, it may occur if California sea lions
are in the same area mingled with the northern elephant seals and the
sea lions react strongly. Responsiveness also varies with time of year
and age class, with juvenile pinnipeds being more likely to react by
leaving the haulout site. The probability and type of behavioral
response will also depend on the season, the group composition of the
pinnipeds, and the type of activity in which they are engaged. For
example, in some cases, harbor seals at SNI appear to be more
responsive during the pupping/breeding season (Holst et al. 2005a;
Holst et al. 2008), while in others, mothers and pups seem to react
less to launches than lone individuals (Ugoretz and Greene Jr. 2012),
and California sea lions seem to be consistently less responsive during
the pupping season (Holst et al. 2010; Holst et al. 2005a; Holst et al.
2008; Holst et al. 2011; Holst et al. 2005b; Ugoretz and Greene Jr.
2012). Though pup abandonment could theoretically result from these
reactions, site-specific monitoring data indicate that pup abandonment
is not likely to occur as a result of the specified activity because it
has not been previously observed. While the reactions are variable, and
can involve abrupt movements by some individuals, biological impacts of
these responses appear to be limited. The responses are not expected to
result in significant injury or mortality, or long-term negative
consequences to individuals or pinniped populations on SNI.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are
[[Page 37810]]
predictable and unvarying. 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. Behavioral state may
affect the type of response as well. For example, animals that are
resting may show greater behavioral change in response to disturbing
sound levels than animals that are highly motivated to remain in an
area for feeding (Richardson et al., 1995; NRC, 2003; Wartzok et al.,
2003).
It is possible that launch-induced flushing or stampedes could have
adverse impacts on individual pinnipeds on the west end of SNI. Bowles
and Stewart (1980) reported that harbor seals on San Miguel Island
reacted to low-altitude jet overflights with alert postures and often
with rapid movement across the haulout sites, especially when aircraft
were visible. However, on SNI during missile launches in 2001-2017,
there was no evidence of launch noise-related injuries or deaths (Burke
2017; Holst et al. 2010; Holst et al. 2005a; Holst et al. 2008; Holst
et al. 2011; Ugoretz 2016; Ugoretz and Greene Jr. 2012). On several
occasions, harbor seals and California sea lion adults moved near and
sometimes over older pups (i.e., greater than four months old) as the
animals moved in response to the launch noises, but the pups were not
injured (Holst et al., 2010; Holst et al., 2005a; Holst et al., 2008;
Holst et al., 2011; Ugoretz and Greene Jr. 2012).
Vessel Strike
Vessel strikes from commercial, recreational, and military vessels
are known to affect large whales and have resulted in serious injury
and occasional fatalities to cetaceans (Berman-Kowalewski et al., 2010;
Calambokidis, 2012; Douglas et al., 2008; Laggner 2009; Lammers et al.,
2003). Records of collisions date back to the early 17th century, and
the worldwide number of collisions appears to have increased steadily
during recent decades (Laist et al., 2001; Ritter 2012).
Numerous studies of interactions between surface vessels and marine
mammals have demonstrated that free-ranging marine mammals often, but
not always (e.g., McKenna et al., 2015), engage in avoidance behavior
when surface vessels move toward them. It is not clear whether these
responses are caused by the physical presence of a surface vessel, the
underwater noise generated by the vessel, or an interaction between the
two (Amaral and Carlson, 2005; Au and Green, 2000; Bain et al., 2006;
Bauer 1986; Bejder et al., 1999; Bejder and Lusseau, 2008; Bejder et
al., 2009; Bryant et al., 1984; Corkeron, 1995; Erbe, 2002;
F[eacute]lix, 2001; Goodwin and Cotton, 2004; Lemon et al., 2006;
Lusseau, 2003; Lusseau, 2006; Magalhaes et al., 2002; Nowacek et al.,
2001; Richter et al., 2003; Scheidat et al., 2004; Simmonds, 2005;
Watkins, 1986; Williams et al., 2002; Wursig et al., 1998). Several
authors suggest that the noise generated during motion is probably an
important factor (Blane and Jaakson, 1994; Evans et al., 1992; Evans et
al., 1994). Water disturbance may also be a factor. These studies
suggest that the behavioral responses of marine mammals to surface
vessels are similar to their behavioral responses to predators.
Avoidance behavior is expected to be even stronger in the subset of
instances during which the Navy is conducting training or testing
activities using explosives.
The marine mammals most vulnerable to vessel strikes are those that
spend extended periods of time at the surface in order to restore
oxygen levels within their tissues after deep dives (e.g., sperm
whales). In addition, some baleen whales seem generally unresponsive to
vessel sound, making them more susceptible to vessel collisions
(Nowacek et al., 2004). These species are primarily large, slow moving
whales.
Some researchers have suggested the relative risk of a vessel
strike can be assessed as a function of animal density and the
magnitude of vessel traffic (e.g., Fonnesbeck et al., 2008; Vanderlaan
et al., 2008). Differences among vessel types also influence the
probability of a vessel strike. The ability of any ship to detect a
marine mammal and avoid a collision depends on a variety of factors,
including environmental conditions, ship design, size, speed, and
ability and number of personnel observing, as well as the behavior of
the animal. Vessel speed, size, and mass are all important factors in
determining if injury or death of a marine mammal is likely due to a
vessel strike. For large vessels, speed and angle of approach can
influence the severity of a strike. For example, Vanderlaan and Taggart
(2007) found that, between vessel speeds of 8.6 and 15 knots, the
probability that a vessel strike is lethal increases from 0.21 to 0.79.
Large whales also do not have to be at the water's surface to be
struck. Silber et al. (2010) found when a whale is below the surface
(about one to two times the vessel draft), under certain circumstances
(vessel speed and location of the whale relative to the ship's
centerline), there is likely to be a pronounced propeller suction
effect. This suction effect may draw the whale into the hull of the
ship, increasing the probability of propeller strikes.
There are some key differences between the operation of military
and non-military vessels, which make the likelihood of a military
vessel striking a whale lower than some other vessels (e.g., commercial
merchant vessels). Key differences include:
<bullet> Many military ships have their bridges positioned closer
to the bow, offering better visibility ahead of the ship (compared to a
commercial merchant vessel);
<bullet> There are often aircraft associated with the training or
testing activity (which can serve as Lookouts), which can more readily
detect cetaceans in the vicinity of a vessel or ahead of a vessel's
present course before crew on the vessel would be able to detect them;
<bullet> Military ships are generally more maneuverable than
commercial merchant vessels, and if cetaceans are spotted in the path
of the ship, could be capable of changing course more quickly;
<bullet> The crew size on military vessels is generally larger than
merchant ships, allowing for stationing more trained Lookouts on the
bridge. At all times when Navy vessels are underway, trained Lookouts
and bridge navigation teams are used to detect objects on the surface
of the water ahead of the ship, including cetaceans. Additional
Lookouts, beyond those already stationed on the bridge and on
navigation teams, are positioned as Lookouts during some training
events; and
<bullet> When submerged, submarines are generally slow moving (to
avoid detection) and therefore marine mammals at depth with a submarine
are likely able to avoid collision with the submarine. When a submarine
is transiting on the surface, there are Lookouts serving the same
function as they do on surface ships.
While there have been vessel strikes documented with commercial
vessels, NMFS has no documented vessel strikes of marine mammals by the
Navy in the PMSR Study Area since the Navy started keeping records of
ship strike in 1995. The only large Navy vessels homebased in the PMSR
local area (Port Hueneme) are the Self Defense Test Ship and the Mobile
Ship Target, which are both greater than 200 ft in length. There are
smaller vessels used either as targets or for target recovery as well.
The majority of Navy vessels (e.g., LCS, destroyers) used during
testing and training on the PMSR Study Area transit from San Diego Navy
bases and typically transit further offshore and enter/exit the PMSR
Study Area from
[[Page 37811]]
the southwestern boundaries to avoid commercial vessel traffic in and
out of the Ports or Los Angeles/Long Beach via the Santa Barbara
Channel.
The Navy transits at safer speeds and has other protective measures
in place during transits, such as using Lookouts and maintaining safe
distances from marine mammals (e.g., 500 yd (457.2 m) for whales and
200 yd (182.88 m) around other marine mammals except bow-riding
dolphins and pinnipeds hauled out on man-made navigational structures,
port structures, and vessels). A DoD funded study (Mintz, 2016) on
commercial and military vessel traffic in Southern California found
that median vessel speed for Navy vessels in the Santa Barbara Channel
and nearshore areas of the PMSR Study Area and SOCAL (part of the HSTT
Study Area) was between 3 to 8 knots. Speed increased as vessels
transited further offshore, between 10-16 knots, with the higher value
on the furthest offshore areas of the PMSR Study Area. Commercial
tankers and cargo median vessel speeds were between 8-14 knots for the
same nearshore areas. Mintz (2016) indicated that Navy vessels make up
only 4 percent of the overall vessel traffic off Southern California
(PMSR/SOCAL). The data collected for Mintz (2016) was collected via AIS
for commercial vessel data and SeaLink for military vessels (a
classified Navy/Coast Guard database maintained by the Office of Naval
Intelligence). The median surface speed of two of the classes of
vessels used on the PMSR Study Area from 2011 through 2015 was below 12
knots. This median speed includes those training and testing operations
that require elevated speeds, and being slightly above 10 knots,
indicates that Naval vessels typically operate at speeds that would be
expected to reduce the potential of vessel strike of a marine mammal.
The Navy has several standard operating procedures for vessel
safety that could result in a secondary benefit to marine mammals
through a reduction in the potential for vessel strike. For example,
ships operated by or for the Navy have personnel assigned to stand
watch at all times, day and night, when moving through the water (i.e.,
when the vessel is underway). Watch personnel undertake extensive
training in accordance with the U.S. Navy Lookout Training Handbook or
civilian equivalent. A primary duty of watch personnel is to ensure
safety of the ship, which includes the requirement to detect and report
all objects and disturbances sighted in the water that may be
indicative of a threat to the ship and its crew, such as debris, a
periscope, surfaced submarine, or surface disturbance. Per safety
requirements, watch personnel also report any marine mammals sighted
that have the potential to be in the direct path of the ship, as a
standard collision avoidance procedure. Navy vessels are required to
operate in accordance with applicable navigation rules. These rules
require that vessels proceed at a safer speed so proper and effective
action can be taken to avoid collision and so vessels can be stopped
within a distance appropriate to the prevailing circumstances and
conditions. In addition to complying with navigation requirements, Navy
ships transit at speeds that are optimal for fuel conservation, to
maintain ship schedules, and to meet mission requirements. Vessel
captains use the totality of the circumstances to ensure the vessel is
traveling at appropriate speeds in accordance with navigation. This
Navy message is also consistent with a message issued by the U.S. Coast
Guard for vessels operating in the 11th district (covering the waters
in and around the PMSR) as a Notice to Mariners that also informs
operators about the presence of populations of blue, humpback, and fin
whales in the area (see U.S. Coast Guard (2019) for further details).
For more information, please see section 3.7.1.1.1 Vessels as a
Strike Stressor in the 2020 PMSR DEIS/OEIS. Additionally, the Navy has
fewer vessel transits than commercial entities in the PMSR Study Area.
To put the PMSR Navy vessel operations level in perspective, Table 6
includes an estimate of annual commercial shipping activity compared
with vessel use in the PMSR Study Area. These annual estimates are
representable of any given year as proposed for this rule. Navy vessels
account for only about nine percent of the vessel traffic within the
PMSR Study Area.
[GRAPHIC] [TIFF OMITTED] TP16JY21.003
In addition, large Navy vessels (greater than 18 m in length)
within the offshore areas of range complexes and testing ranges operate
differently from commercial vessels in ways that may reduce potential
for whale collisions. Surface ships operated by or for the Navy have
multiple personnel assigned to stand watch at all times, when a ship or
surfaced submarine is moving through the water (underway). A primary
duty of personnel standing watch on surface ships is to detect and
report all objects and disturbances sighted in the water that may
indicate a threat to the vessel and its crew, such as debris, a
periscope, surfaced submarine, or surface disturbance. Per vessel
safety requirements, personnel standing watch also report any marine
mammals sighted in the path of the vessel as a standard collision
avoidance procedure. All vessels proceed at a safer speed so they can
take proper and effective action to avoid a collision with any sighted
object or disturbance, and can be stopped within a distance appropriate
to the prevailing circumstances and conditions.
Between 2007 and 2009, the Navy developed and distributed
additional training, mitigation, and reporting tools to Navy operators
to improve marine
[[Page 37812]]
mammal protection and to ensure compliance with LOA requirements. In
2009, the Navy implemented Marine Species Awareness Training designed
to improve effectiveness of visual observation for marine resources,
including marine mammals. For over a decade, the Navy has implemented
the Protective Measures Assessment Protocol software tool, which
provides operators with notification of the required mitigation and a
visual display of the planned training or testing activity location
overlaid with relevant environmental data.
The Navy does not anticipate vessel strikes and has not requested
authorization to take marine mammals by serious injury or mortality
within the PMSR Study Area during training and testing activities. NMFS
agrees with the Navy's conclusions based on this qualitative analysis;
therefore, NMFS has preliminarily determined that the Navy's decision
not to request take authorization for vessel strike of large whales is
supported by multiple factors, including no previous instances of
strikes by Navy vessels in the PMSR Study Area, relatively low at-sea
days compared to other Navy training and testing study areas, fewer
vessels used compared to other Navy training and testing study areas,
ways in which the larger vessels operate in the PMSR Study Area, and
the mitigation measures that would be in place to further minimize
potential vessel strike.
In addition to the reasons listed above that make it unlikely that
the Navy will hit a large whale (more maneuverable ships, larger crew,
etc.), the following are additional reasons that vessel strike of
dolphins and small whales is very unlikely. Dating back more than 20
years and for as long as it has kept records, the Navy has no records
of individuals of these groups being struck by a vessel as a result of
Navy activities and, further, their smaller size and maneuverability
make a strike unlikely. Also, NMFS has never received any reports from
other authorized activities indicating that these species have been
struck by vessels. Worldwide ship strike records show little evidence
of strikes of these groups from the shipping sector and larger vessels,
and the majority of the Navy's activities involving faster-moving
vessels (that could be considered more likely to hit a marine mammal)
are located in offshore areas where smaller delphinid densities are
lower. Based on this information, NMFS concurs with the Navy's
assessment that vessel strike is not likely to occur for either large
whales or smaller marine mammals.
Marine Mammal Habitat
Impacts on marine mammal habitat are part of the consideration in
making a finding of negligible impact on the species and stocks of
marine mammals. Habitat includes, but is not necessarily limited to,
rookeries, mating grounds, feeding areas, and areas of similar
significance. We do not anticipate that the Navy's proposed activities
would result in permanent effects on the habitats used by the marine
mammals in the PMSR Study Area, including the availability of prey
(i.e., fish and invertebrates). While it is anticipated that the
proposed activity may result in marine mammals avoiding certain areas
due to temporary ensonification, this impact to habitat is temporary
and reversible and was considered in further detail earlier in this
document, as behavioral modification. The main impact associated with
the proposed activity will be temporarily elevated noise levels and the
associated direct effects on marine mammals, previously discussed in
this notice.
Effects to Prey--Sound may affect marine mammals through impacts on
the abundance, behavior, or distribution of prey species (e.g.,
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies
by species, season, and location and, for some species, is not well
documented. Here, we describe studies regarding the effects of noise on
known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
The most likely effects on fishes exposed to loud, intermittent, low-
frequency sounds are behavioral responses (i.e., flight or avoidance).
Short duration, sharp sounds (such as pile driving or air guns) can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to acoustic sources depends on the physiological
state of the fish, past exposures, motivation (e.g., feeding, spawning,
migration), and other environmental factors. Key impacts to fishes may
include behavioral responses, hearing damage, barotrauma (pressure-
related injuries), and mortality.
Fishes, like other vertebrates, have a variety of different sensory
systems to glean information from ocean around them (Astrup and Mohl,
1993; Astrup, 1999; Braun and Grande, 2008; Carroll et al., 2017;
Hawkins and Johnstone, 1978; Ladich and Popper, 2004; Ladich and
Schulz-Mirbach, 2016; Mann, 2016; Nedwell et al., 2004; Popper et al.,
2003; Popper et al., 2005). 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) (terrestrial
vertebrates generally only detect pressure). Most marine fishes
primarily detect particle motion using the inner ear and lateral line
system, while some fishes possess additional morphological adaptations
or specializations that can enhance their sensitivity to sound
pressure, such as a gas-filled swim bladder (Braun and Grande, 2008;
Popper and Fay, 2011).
Hearing capabilities vary considerably between different fish
species with data only available for just over 100 species out of the
34,000 marine and freshwater fish species (Eschmeyer and Fong, 2016).
In order to better understand acoustic impacts on fishes, fish hearing
groups are defined by species that possess a similar continuum of
anatomical features which result in varying degrees of hearing
sensitivity (Popper and Hastings, 2009a). There are four hearing groups
defined for all fish species (modified from Popper et al., 2014) within
this analysis and they include: Fishes without a swim bladder (e.g.,
flatfish, sharks, rays, etc.); fishes with a swim bladder not involved
in hearing (e.g., salmon, cod, pollock, etc.); fishes with a swim
bladder involved in hearing (e.g., sardines, anchovy, herring, etc.);
and fishes with a swim bladder involved in hearing and high-frequency
hearing (e.g., shad and menhaden). Currently, less data are available
to estimate the range of best sensitivity for fishes without a swim
bladder.
In terms of behavioral responses of fish, Juanes et al. (2017)
discuss the potential for negative impacts from anthropogenic
soundscapes on fish, but the author's focus was on broader based sounds
such as ship and boat noise sources. Occasional behavioral reactions to
intermittent explosions occurring at or near the surface are unlikely
to cause long-term consequences for individual fish or populations;
there are no detonations of explosives occurring underwater from the
proposed activities. Fish that experience hearing loss as a result of
exposure to explosions may have a reduced ability to detect relevant
sounds such as predators, prey, or social vocalizations. However, PTS
has not been known to occur in fishes and any hearing loss in fish may
be as temporary as the timeframe required to repair or replace the
sensory cells that were damaged or destroyed (Popper et al., 2005;
Popper et al., 2014; Smith et al., 2006). It is not known if damage to
[[Page 37813]]
auditory nerve fibers could occur, and if so, whether fibers would
recover during this process. It is also possible for fish to be injured
or killed by an explosion in the immediate vicinity of the surface from
dropped or fired ordnance. Physical effects from pressure waves
generated by detonations at or near the surface could potentially
affect fish within proximity of training or testing activities. The
shock wave from occurring at or near the surface may be lethal to fish
at close range, causing massive organ and tissue damage and internal
bleeding (Keevin and Hempen, 1997). At greater distance from the
detonation point, the extent of mortality or injury depends on a number
of factors including fish size, body shape, orientation, and species
(Keevin and Hempen, 1997; Wright, 1982). At the same distance from the
source, larger fish are generally less susceptible to death or injury,
elongated forms that are round in cross-section are less at risk than
deep-bodied forms, and fish oriented sideways to the blast suffer the
greatest impact (Edds-Walton and Finneran, 2006; O'Keeffe, 1984;
O'Keeffe and Young, 1984; Wiley et al., 1981; Yelverton et al., 1975).
Species with gas-filled organs are more susceptible to injury and
mortality than those without them (Gaspin, 1975; Gaspin et al., 1976;
Goertner et al., 1994).
Fish not killed or driven from a location by an explosion might
change their behavior, feeding pattern, or distribution. Changes in
behavior of fish have been observed as a result of sound produced by
explosives, with effect intensified in areas of hard substrate (Wright,
1982). However, Navy would avoid hard substrate to the best extent
practical in the course of their activities. Training and testing
exercises involving explosions at or near the surface are dispersed in
space and time; therefore, repeated exposure of individual fishes are
unlikely. Mortality and injury effects to fishes from explosives would
be localized around the area of a given explosion, but only if
individual fish and the explosive at the surface were co-located at the
same time. Fishes deeper in the water column or on the bottom would not
be affected by surface explosions. Long-term consequences for fish
populations, including key prey species within the PMSR Study Area,
would not be expected.
Vessels and in-water devices do not normally collide with adult
fish, most of which can detect and avoid them. Exposure of fishes to
vessel strike stressors is limited to those fish groups that are large,
slow-moving, and may occur near the surface, such as ocean sunfish,
whale sharks, basking sharks, and manta rays. These species are
distributed widely in offshore portions of the PMSR Study Area. Any
isolated cases of a Navy vessel striking an individual could injure
that individual, impacting the fitness of an individual fish. Vessel
strikes would not pose a risk to most of the other marine fish groups,
because many fish can detect and avoid vessel movements, making strikes
rare and allowing the fish to return to their normal behavior after the
ship or device passes. As a vessel approaches a fish, they could have a
detectable behavioral or physiological response (e.g., swimming away
and increased heart rate) as the passing vessel displaces them.
However, such reactions are not expected to have lasting effects on the
survival, growth, recruitment, or reproduction of these marine fish
groups at the population level and therefore would not have an impact
on marine mammal species as prey items.
In addition to fish, prey sources such as marine invertebrates
could potentially be impacted by sound stressors as a result of the
proposed activities. However, most marine invertebrates' ability to
sense sounds is very limited. In most cases, marine invertebrates would
not respond to impulsive sounds. Data on response of invertebrates such
as squid, another marine mammal prey species, to anthropogenic sound
has been documented (de Soto, 2016; Sole et al., 2017b). Explosions
could kill or injure nearby marine invertebrates. Vessels also have the
potential to impact marine invertebrates by disturbing the water column
or sediments, or directly striking organisms (Bishop, 2008). The
propeller wash (water displaced by propellers used for propulsion) from
vessel movement and water displaced from vessel hulls can potentially
disturb marine invertebrates in the water column and is a likely cause
of zooplankton mortality (Bickel et al., 2011). The localized and
short-term exposure to at or near the surface explosions or vessels
could displace, injure, or kill zooplankton, invertebrate eggs or
larvae, and macro-invertebrates. However, mortality or long-term
consequences for a few animals is unlikely to have measurable effects
on overall populations. Long-term consequences to marine invertebrate
populations would not be expected as a result of exposure to sounds of
vessels in the PMSR Study Area.
Military expended materials resulting from training and testing
activities could potentially result in minor long-term changes to
benthic habitat, however the impacts of small amounts of expended
materials are unlikely to have measurable effects on overall
populations. Military expended materials may be colonized over time by
benthic organisms that prefer hard substrate and would provide
structure that could attract some species of fish or invertebrates.
Overall, the combined impacts of sound exposure, explosions, vessel
strikes, and military expended materials resulting from the proposed
activities would not be expected to have measurable effects on
populations of marine mammal prey species. Prey species exposed to
sound might move away from the sound source or show no obvious direct
effects at all, but a rapid return to normal recruitment, distribution,
and behavior is anticipated. Long-term consequences to fish or marine
invertebrate populations would not be expected as a result of exposure
to sounds or vessels in the PMSR Study Area.
Acoustic Habitat--Acoustic habitat is the soundscape which
encompasses all of the sound present in a particular location and time,
as a whole when considered from the perspective of the animals
experiencing it. Animals produce sound for, or listen for sounds
produced by, conspecifics (communication during feeding, mating, and
other social activities), other animals (finding prey or avoiding
predators), and the physical environment (finding suitable habitats,
navigating). Together, sounds made by animals and the geophysical
environment (e.g., produced by earthquakes, lightning, wind, rain,
waves) make up the natural contributions to the total acoustics of a
place. These acoustic conditions, termed acoustic habitat, are one
attribute of an animal's total habitat.
Soundscapes are also defined by, and acoustic habitat influenced
by, the total contribution of anthropogenic sound. This may include
incidental emissions from sources such as vessel traffic or may be
intentionally introduced to the marine environment for data acquisition
purposes (e.g., as in the use of air gun arrays) or for Navy training
and testing purposes (as in the use of explosives, and target and
missile launches on SNI). Anthropogenic noise varies widely in its
frequency, content, duration, and loudness, and these characteristics
greatly influence the potential habitat-mediated effects to marine
mammals, which may range from local effects for brief periods of time
to chronic effects over large areas and for long durations. Depending
on the extent of effects to habitat, animals may alter their
communications signals (thereby
[[Page 37814]]
potentially expending additional energy) or miss acoustic cues (either
conspecific or adventitious). Problems arising from a failure to detect
cues are more likely to occur when noise stimuli are chronic and
overlap with biologically relevant cues used for communication,
orientation, and predator/prey detection (Francis and Barber, 2013).
For more detail on these concepts see, e.g., Barber et al., 2009;
Pijanowski et al., 2011; Francis and Barber, 2013; Lillis et al., 2014.
We do not anticipate these problems arising from at or near surface
explosions or from launched targets and missiles produced during
training and testing activities as they would be more widely dispersed
or concentrated in small areas for shorter periods of time.
Anthropogenic noise attributable to Navy testing and training
activities in the PMSR Study Area emanates from multiple sources
including explosives, vessels, and launched targets and missiles
occurring in the vicinity of pinniped haul out sites. Sound produced
from training and testing activities in the PMSR Study Area would be
temporary and transitory; the affected area would be expected to
immediately return to the original state when these activities cease.
Water Quality--Training and testing activities may introduce water
quality constituents into the water column. Based on the analysis of
the 2020 PMSR DSEIS/OEIS, military expended materials (e.g.,
undetonated explosive materials) would be released in quantities and at
rates that would not result in a violation of any water quality
standard or criteria. NMFS has reviewed this analysis and concurs that
it reflects the best available science. High-order explosions consume
most of the explosive material, creating typical combustion products.
For example, in the case of the Royal Demolition Explosive, 98 percent
of the products are common seawater constituents and the remainder is
rapidly diluted below threshold effect level. Explosion by-products
associated with high order detonations present no secondary stressors
to marine mammals through sediment or water. However, low order
detonations and unexploded ordnance present elevated likelihood of
impacts on marine mammals.
Indirect effects of explosives and unexploded ordnance to marine
mammals via sediment is possible in the immediate vicinity of the
ordnance. Degradation products of the Royal Demolition Explosive are
not toxic to marine organisms at realistic exposure levels (Rosen and
Lotufo, 2010). Relatively low solubility of most explosives and their
degradation products means that concentrations of these contaminants in
the marine environment are relatively low and readily diluted.
Furthermore, while explosives and their degradation products were
detectable in marine sediment approximately 6-12 in (0.15-0.3 m) away
from degrading ordnance, the concentrations of these compounds were not
statistically distinguishable from background beyond 3-6 ft (1-2 m)
from the degrading ordnance. Taken together, it is possible that marine
mammals could be exposed to degrading explosives, but it would be
within a very small radius of the explosive (1-6 ft (0.3-2 m)).
Equipment used by the Navy within the PMSR Study Area, including
ships and other marine vessels, aircraft, and other equipment, are also
potential sources of by-products. All equipment is properly maintained
in accordance with applicable Navy and legal requirements. All such
operating equipment meets Federal water quality standards, where
applicable.
Airborne Launch Sounds on SNI--Various beaches around SNI are used
by pinnipeds as places to rest, molt, and breed. These beaches consist
of sand (e.g., Red Eye Beach), rock ledges (e.g., Phoca Reef), and
rocky cobble (e.g., Bachelor Beach). Pinnipeds continue to use beaches
around the western end of SNI, and indeed are expanding their use of
some beaches despite ongoing launch activities for many years.
Similarly, it appears that sounds from prior launches have not affected
pinniped use of coastal areas at VAFB.
Pinnipeds forage in the open ocean and in the waters near SNI;
however, the airborne launch sounds would not persist in the water near
SNI. Therefore, it is not expected that the launch activities would
impact prey resources, Essential Fish Habitat (EFH), or feeding success
of pinnipeds. Three types of EFH are present in the activity area:
Groundfish, coastal pelagic species, and highly migratory species, as
well as canopy kelp Habitat Areas of Particular Concern (HAPC).
However, none of these types of EFH or HAPC will be impacted by the
proposed activity.
Boosters from missiles (e.g., jet-assisted take off rocket bottles
for BQM drone missiles) may be jettisoned shortly after launch and fall
on the island and would be collected, but are not expected to impact
beaches. Fuel contained in these boosters is consumed rapidly and
completely, so there would be no risk of contamination even in the very
unlikely event that a booster did land on a beach or nearshore waters.
Overall, the proposed missile launch activity is not expected to cause
significant impacts or have permanent, adverse effects on pinniped
habitats or on their foraging habitats and prey.
Estimated Take of Marine Mammals
This section indicates the number of takes that NMFS is proposing
to authorize, which is based on the maximum amount that is reasonably
likely to occur, depending on the type of take and the methods used to
estimate it, as described in detail below. NMFS coordinated closely
with the Navy in the development of their incidental take application,
and preliminarily agrees that the methods the Navy has put forth
described herein to estimate take (including the model, thresholds, and
density estimates), and the resulting numbers estimated for
authorization, are appropriate and based on the best available science.
All takes are by harassment. For a military readiness activity, the
MMPA defines ``harassment'' as (i) Any act that injures or has the
significant potential to injure a marine mammal or marine mammal stock
in the wild (Level A Harassment); or (ii) Any act that disturbs or is
likely to disturb a marine mammal or marine mammal stock in the wild by
causing disruption of natural behavioral patterns, including, but not
limited to, migration, surfacing, nursing, breeding, feeding, or
sheltering, to a point where such behavioral patterns are abandoned or
significantly altered (Level B Harassment). No serious injury or
mortality of marine mammals is expected to occur.
Proposed authorized takes would primarily be in the form of Level B
harassment, as use of the explosive sources and may result, either
directly or as result of TTS, in the disruption of natural behavioral
patterns to a point where they are abandoned or significantly altered
(as defined specifically at the beginning of this section, but referred
to generally as behavioral disruption). There is also the potential for
Level A harassment, in the form of auditory injury to result from
exposure to the sound sources utilized in training and testing
activities.
Generally speaking, for acoustic impacts NMFS estimates the amount
and type of harassment by considering: (1) Acoustic thresholds above
which NMFS believes the best available science indicates marine mammals
will be taken by Level B harassment or incur some degree of temporary
or permanent hearing impairment; (2) the area or volume of water that
will be ensonified above these levels in a day or event; (3) the
density or occurrence of marine mammals within these ensonified areas;
[[Page 37815]]
and (4) the number of days of activities or events.
Acoustic Thresholds
Using the best available science, NMFS, in coordination with the
Navy, has established acoustic thresholds that identify the most
appropriate received level of underwater sound above which marine
mammals exposed to these sound sources could be reasonably expected to
directly experience a disruption in behavior patterns to a point where
they are abandoned or significantly altered, to incur TTS (equated to
Level B harassment), or to incur PTS of some degree (equated to Level A
harassment). Thresholds have also been developed to identify the
pressure levels above which animals may incur non-auditory injury from
exposure to pressure waves from explosive detonation. Refer to the
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects
Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for
detailed information on how the criteria and thresholds were derived.
Despite the quickly evolving science, there are still challenges in
quantifying expected behavioral responses that qualify as take by Level
B harassment, especially where the goal is to use one or two
predictable indicators (e.g., received level and distance) to predict
responses that are also driven by additional factors that cannot be
easily incorporated into the thresholds (e.g., context). So, while the
behavioral harassment thresholds have been refined here to better
consider the best available science (e.g., incorporating both received
level and distance), they also still have some built-in conservative
factors to address the challenge noted. For example, while duration of
observed responses in the data are now considered in the thresholds,
many of the responses that are informing take thresholds are of a very
short duration, such that it is possible that responses will not rise
to the level of disrupting behavior patterns to a point where they are
abandoned or significantly altered. We describe the application of this
behavioral harassment threshold as identifying the maximum number of
instances in which marine mammals could be reasonably expected to
experience a disruption in behavior patterns to a point where they are
abandoned or significantly altered. In summary, we believe these
behavioral harassment thresholds are the most appropriate method for
predicting Level B harassment by behavioral disturbance given the best
available science and the associated uncertainty.
Hearing Impairment (TTS/PTS), Tissues Damage, and Mortality
NMFS' Acoustic Technical Guidance (NMFS, 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 Acoustic Technical Guidance also
identifies criteria to predict TTS, which is not considered injury and
falls into the Level B harassment category. The Navy's proposed
activity only includes the use of impulsive (explosives) sources. These
thresholds (Table 7) were developed by compiling and synthesizing the
best available science and soliciting input multiple times from both
the public and peer reviewers. The references, analysis, and
methodology used in the development of the thresholds are described in
Acoustic Technical Guidance, which may be accessed 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>.
Based on the best available science, the Navy (in coordination with
NMFS) used the acoustic and pressure thresholds indicated in Table 7 to
predict the onset of TTS, PTS, tissue damage, and mortality for
explosives (impulsive) and other impulsive sound sources.
Table 7--Onset of TTS, PTS, Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives and Other Impulsive Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mean onset slight Mean onset slight Mean onset
Functional hearing group Species Onset TTS Onset PTS GI tract injury lung injury mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans......... All mysticetes.... 168 dB SEL 183 dB SEL 237 dB Peak SPL... Equation 1........ Equation 2
(weighted) or 213 (weighted). or
dB Peak SPL. 219 dB Peak SPL.
Mid-frequency cetaceans......... Most delphinids, 170 dB SEL 185 dB SEL 237 dB Peak SPL...
medium and large (weighted) or 224 (weighted) or 230
toothed whales. dB Peak SPL. dB Peak SPL.
High-frequency cetaceans........ Porpoises and 140 dB SEL 155 dB SEL 237 dB Peak SPL...
Kogia spp. (weighted) or 196 (weighted) or 202
dB Peak SPL. dB Peak SPL.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
Equation 1: 47.5M1/3 (1+[DRm/10.1])1/6 Pa-sec.
Equation 2: 103M1/3 (1+[DRm/10.1])1/6 Pa-sec.
M = mass of the animals in kg.
DRm = depth of the receiver (animal) in meters.
SPL = sound pressure level.
Refer to the Criteria and Thresholds for U.S. Navy Acoustic and
Explosive Effects Analysis (Phase III) report (U.S. Department of the
Navy, 2017c) for detailed information on how the criteria and
thresholds were derived. Non-auditory injury (i.e., other than PTS) and
mortality are so unlikely as to be discountable under normal conditions
and are therefore not considered further in this analysis.
The mitigation measures associated with explosives are expected to
be effective in preventing non-auditory tissue damage to any
potentially affected species, and when considered in combination with
the modeled
[[Page 37816]]
exposure results, no species are anticipated to incur non-auditory
tissue damage during the period of this rule. Table 16 indicates the
range of effects for tissue damage for different explosive types. The
Navy will implement mitigation measures (described in the Proposed
Mitigation Measures section) during explosive activities, including
delaying detonations when a marine mammal is observed in the mitigation
zone. Nearly all explosive events will occur during daylight hours to
improve the sightability of marine mammals and thereby improve
mitigation effectiveness. Observing for marine mammals during the
explosive activities will include visual methods before the activity
begins, in order to cover the mitigation zone (e.g., 2,500 yds (2,286
m) for explosive bombs).
Behavioral Disturbance
Though significantly driven by received level, the onset of Level B
harassment by direct behavioral disturbance from anthropogenic noise
exposure is also informed to varying degrees by other factors related
to the source (e.g., frequency, predictability, duty cycle, distance),
the environment (e.g., bathymetry), and the receiving animals (hearing,
motivation, experience, demography, behavioral context) and can be
difficult to predict (Ellison et al., 2011; Southall et al., 2007).
Based on what the available science indicates and the practical need to
use thresholds based on a factor, or factors, that are both predictable
and measurable for most activities, NMFS uses generalized acoustic
thresholds based primarily on received level (and distance in some
cases) to estimate the onset of Level B harassment by behavioral
disturbance.
Explosives--Explosive thresholds for Level B harassment by
behavioral disturbance for marine mammals are the hearing groups' TTS
thresholds minus 5 dB (see Table 8 below and Table 7 for the TTS
thresholds for explosives) for events that contain multiple impulses
from explosives underwater. This was the same approach as taken in
Phase II and Phase III for explosive analysis in other Navy training
and testing Study Areas. See the Criteria and Thresholds for U.S. Navy
Acoustic and Explosive Effects Analysis (Phase III) report (U.S.
Department of the Navy, 2017c) for detailed information on how the
criteria and thresholds were derived. NMFS continues to concur that
this approach represents the best available science for determining
behavioral disturbance of marine mammals from multiple explosives.
While marine mammals may also respond to single explosive detonations,
these responses are expected to more typically be in the form of
startle reaction, rather than a disruption in natural behavioral
patterns to the point where they are abandoned or significantly
altered. On the rare occasion that a single detonation might result in
a more severe behavioral response that qualifies as Level B harassment,
it would be expected to be in response to a comparatively higher
received level. Accordingly, NMFS considers the potential for these
responses to be quantitatively accounted for through the application of
the TTS threshold, which as noted above is 5dB higher than the
behavioral harassment threshold for multiple explosives.
Table 8--Thresholds for Level B Harassment by Behavioral Disturbance for
Explosives for Marine Mammals
------------------------------------------------------------------------
Functional hearing
Medium group SEL (weighted)
------------------------------------------------------------------------
Underwater........................ LF.................. 163
Underwater........................ MF.................. 165
Underwater........................ HF.................. 135
Underwater........................ Otariids............ 183
Underwater........................ Phocids............. 165
------------------------------------------------------------------------
Note: Weighted SEL thresholds in dB re 1 [mu]Pa\2\s underwater. LF = low-
frequency, MF = mid-frequency, HF = high-frequency.
Navy's Acoustic Effects Model
The Navy's Acoustic Effects Model calculates sound energy
propagation from sonar and other transducers and explosives during
naval activities and the sound received by animat dosimeters. Animat
dosimeters are virtual representations of marine mammals distributed in
the area around the modeled naval activity and each dosimeter records
its individual sound ``dose.'' The model bases the distribution of
animats over the PMSR Study Area on the density values in the Navy
Marine Species Density Database and distributes animats in the water
column proportional to the known time that species spend at varying
depths.
The model accounts for environmental variability of sound
propagation in both distance and depth when computing the received
sound level received by the animats. The model conducts a statistical
analysis based on multiple model runs to compute the estimated effects
on animals. The number of animats that exceed the thresholds for
effects is tallied to provide an estimate of the number of marine
mammals that could be affected.
Assumptions in the Navy model intentionally err on the side of
overestimation when there are unknowns. Naval activities are modeled as
though they would occur regardless of proximity to marine mammals,
meaning that no mitigation is considered and without any avoidance of
the activity by the animal. The final step of the quantitative analysis
of acoustic effects is to consider the implementation of mitigation and
the possibility that marine mammals would avoid continued or repeated
sound exposures. For more information on this process, see the
discussion in the Take Estimation subsection below. Many explosions
from ordnance such as bombs and missiles actually occur upon impact
with above-water targets. However, for this analysis, sources such as
these were modeled as exploding underwater, which overestimates the
amount of explosive and acoustic energy entering the water.
The model estimates the impacts caused by individual training and
testing exercises. During any individual modeled event, impacts to
individual animats are considered over 24-hour periods. The animats do
not represent actual animals, but rather a distribution of animals
based on density and abundance data, which allows for a statistical
analysis of the number of instances that marine mammals may be exposed
to sound levels resulting in an effect. Therefore, the model estimates
the number of instances in which an effect threshold was exceeded over
the course of a year, but does not estimate the number of individual
marine mammals that may be impacted over a year (i.e., some marine
mammals could be impacted several times, while others would not
experience any impact). A detailed explanation of the Navy's Acoustic
Effects Model is provided in the technical report Quantifying Acoustic
Impacts on Marine Species: Methods and Analytical Approach for
Activities at the Point Mugu Sea Range (U.S. Department of the Navy,
2020).
Range to Effects
The following section provides range (distance) to effects for
explosives, to specific acoustic thresholds determined using the Navy
Acoustic Effects Model. Marine mammals exposed within these ranges for
the shown duration are predicted to experience the associated effect.
Range to effects is important information in not only predicting
acoustic impacts, but also in verifying the accuracy of model results
against real-world situations and determining adequate mitigation
ranges to avoid higher level effects, especially
[[Page 37817]]
physiological effects to marine mammals.
Explosives
The following section provides the range (distance) over which
specific physiological or behavioral effects are expected to occur
based on the explosive criteria (see Section 6, Section 6.5.2.1.1 of
the Navy's rulemaking/LOA application and the Criteria and Thresholds
for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III)
report (U.S. Department of the Navy, 2017c)) and the explosive
propagation calculations from the Navy Acoustic Effects Model (see
Section 6, Section 6.5.2.1.3, Navy Acoustic Effects Model of the Navy's
rulemaking/LOA application). The range to effects is shown for a range
of explosive bins, from E1 (up to 0.25 lb net explosive weight) to E10
(up to 500 lb net explosive weight) (Tables 11 through 17). Explosive
bins not shown on these tables include E2, E4, E7, E11, and E12, as
they are not used in the PMSR Study Area and therefore not included in
Tables 11 through 17. Ranges are determined by modeling the distance
that noise from an explosion would need to propagate to reach exposure
level thresholds specific to a hearing group that would cause
behavioral response (to the degree of Level B harassment), TTS, PTS,
and non-auditory injury. Ranges are provided for a representative
source depth and cluster size for each bin. For events with multiple
explosions, sound from successive explosions can be expected to
accumulate and increase the range to the onset of an impact based on
SEL thresholds. Ranges to non-auditory injury and mortality are shown
in Tables 16 and 17, respectively. NMFS has reviewed the range distance
to effect data provided by the Navy and concurs with the analysis. For
additional information on how ranges to impacts from explosions were
estimated, see the technical report Quantifying Acoustic Impacts on
Marine Species: Methods and Analytical Approach for Activities at the
Point Mugu Sea Range (U.S. Department of the Navy, 2020).
Table 11 shows the minimum, average, and maximum ranges to onset of
auditory and behavioral effects that likely rise to the level of Level
B harassment for high-frequency cetaceans based on the developed
thresholds.
Table 11--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance
for High-Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
Bin Cluster size PTS TTS Behavioral
----------------------------------------------------------------------------------------------------------------
E1............................ 1 353 (130-825) 1,234 (290-3,025) 2,141 (340-4,775)
[…truncated; see source link]Indexed from Federal Register on July 16, 2021.
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