Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Mariana Islands Training and Testing (MITT) Study Area
Federal RegisterJul 31, 2020
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 218
[Docket No. 200713-0188]
RIN 0648-BJ00
Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Mariana Islands Training and Testing (MITT) Study Area
AGENCY:
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION:
Final rule; notification of issuance of Letter of Authorization.
SUMMARY:
NMFS, upon request from the U.S. Navy (Navy), issues these regulations pursuant to the Marine Mammal Protection Act (MMPA) to govern the taking of marine mammals incidental to the training and testing activities conducted in the Mariana Islands Training and Testing (MITT) Study Area. 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). These regulations, which allow for the issuance of a Letter of Authorization (LOA) for the incidental take of marine mammals during the described activities and timeframes, prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species and their habitat, and establish requirements pertaining to the monitoring and reporting of such taking.
DATES:
Effective from July 31, 2020, to July 30, 2027.
ADDRESSES:
A copy of the Navy's application, NMFS' proposed and final rules and subsequent LOA for the existing regulations, and other supporting documents and documents cited herein may be obtained online at:
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
In case of problems accessing these documents, please use the contact listed here (see
FOR FURTHER INFORMATION CONTACT
).
FOR FURTHER INFORMATION CONTACT:
Stephanie Egger, Office of Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These regulations, issued under the authority of the MMPA (16 U.S.C. 1361
et seq.
), 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 sonar and other transducers and in-water detonations throughout the MITT Study Area. The MITT Study Area includes the seas off the coasts of Guam and the Commonwealth of the Northern Mariana Islands (CNMI), the in-water areas around the Mariana Islands Range Complex (MIRC), the transit corridor between the MIRC and the Hawaii Range Complex (HRC), and select pierside and harbor locations. The transit corridor is outside the geographic boundaries of the MIRC and represents a great circle route across the high seas for Navy vessels transiting between the MIRC and the HRC. The planned activities also include various activities in Apra Harbor such as sonar maintenance alongside Navy piers located in Inner Apra Harbor.
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 authorized.
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if, after notice and public comment, the agency makes certain findings and issues regulations that set forth permissible methods of taking pursuant to that activity, as well as monitoring and reporting requirements. Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I, provide the legal basis for issuing this final rule and the subsequent LOAs. As directed by this legal authority, this final rule contains mitigation, monitoring, and reporting requirements.
Summary of Major Provisions Within the Final Rule
The following is a summary of the major provisions of this final rule regarding the Navy's activities. Major provisions include, but are not limited to:
• The use of defined powerdown and shutdown zones (based on activity);
• Measures to eliminate the likelihood of ship strikes;
• Activity limitations in certain areas and times that are biologically important (
i.e.,
for foraging, migration, reproduction) for marine mammals; and
• Implementation of a Notification and Reporting Plan (for dead or live stranded marine mammals); and
• Implementation of a robust monitoring plan to improve our understanding of the environmental effects resulting from the Navy training and testing activities.
Additionally, the rule includes an adaptive management component that allows for timely modification of mitigation or monitoring measures based on new information, when appropriate.
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”); and 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
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 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 February 11, 2019, 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 the use of sonar and other transducers and in-water detonations in the MITT Study Area over a seven-year period beginning when the current authorization expires. On March 15, 2019, we published a notice of receipt of application (NOR) in the
Federal Register
(84 FR 9495), requesting comments and information related to the Navy's request for 30 days. On January 31, 2020, we published a notice of the proposed rulemaking (85 FR 5782) and requested comments and information related to the Navy's request for 45 days. All comments received during the NOR and the proposed rulemaking comment periods were considered in this final rule. Comments received on the proposed rule are addressed in this final rule in the
Comments and Responses
section. 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: Amphibious warfare (in-water detonations), anti-submarine warfare (sonar and other transducers, in-water detonations), surface warfare (in-water detonations), and other testing and training (sonar and other transducers). The activities will not include any pile driving/removal or use of air guns.
This will be the third time NMFS has promulgated incidental take regulations pursuant to the MMPA relating to similar military readiness activities in the MITT Study Area, following those effective from August 3, 2010, through August 3, 2015 (75 FR 45527; August 3, 2010) and from August 3, 2015 through August 3, 2020 (80 FR 46112; August 3, 2015). For this third rulemaking, the Navy is proposing to conduct similar activities as they have conducted over the past nine years under the previous rulemakings.
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 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, but the basic nature of sonar and explosive events conducted in the MITT Study Area has remained the same.
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 regulations will cover training and testing activities that will occur for a seven-year period following the expiration of the current MMPA authorization for the MITT Study Area, which expires on August 3, 2020.
Description of the Specified Activity
Additional detail regarding the specified activity was provided in our
Federal Register
notice of proposed rulemaking (85 FR 5782; January 31, 2020); please see that notice of proposed rulemaking or the Navy's application for more information. In addition, since publication of the proposed rule, additional mitigation measures have been added, which are discussed in detail in the
Mitigation Measures
section of this rule. The Navy requested authorization to take marine mammals incidental to conducting training and testing activities. The Navy has determined that acoustic and explosive stressors 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 MITT Final Supplemental Environmental Impact Statement (FSEIS)/Overseas EIS (OEIS) (2020 MITT FSEIS/OEIS) (U.S. Department of the Navy, 2020) and in the Navy's rule making/LOA application (
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities
) and are summarized here.
Dates and Duration
The specified activities can 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 (see
Mitigation Measures
section). The planned number of training and testing activities are described in the
Detailed Description of the Specified Activities
section (Table 3).
Geographical Region
The MITT Study Area is comprised of three components: (1) The MIRC, (2) additional areas on the high seas, and (3) a transit corridor between the MIRC and the HRC. The MIRC includes the waters south of Guam to north of Pagan (CNMI), and from the Pacific Ocean east of the Mariana Islands to the Philippine Sea to the west, encompassing 501,873 square nautical miles (nmi
2
) of open ocean. The additional areas of the high seas include the area to the north of the MIRC that is within the U.S. Exclusive Economic Zone (EEZ) of the CNMI and the areas to the west of the MIRC. The transit corridor is outside the geographic boundaries of the MIRC and represents a great circle route (
i.e.,
the shortest distance) across the high seas for Navy ships transiting between the MIRC and the HRC. Although not part of any defined range complex, the transit corridor is important to the Navy in that it provides available air, sea, and undersea space where vessels and aircraft conduct training and testing while in transit. While in transit and along the corridor, vessels and aircraft will, at times, conduct basic and routine unit-level activities such as gunnery and sonar training. Ships also conduct sonar maintenance, which includes active sonar transmissions.
Additionally, the MITT Study Area includes pierside locations in the Apra Harbor Naval Complex where surface ship and submarine sonar maintenance occur. Activities in Apra Harbor include channels and routes to and from the Navy port in the Apra Harbor Naval Complex, and associated wharves and facilities within the Navy port.
Primary Mission Areas
The Navy categorizes its at-sea activities into functional warfare areas called primary mission areas. These activities generally fall into the following eight primary mission areas: Air warfare; amphibious warfare; anti-submarine warfare (ASW); electronic warfare; expeditionary warfare; mine warfare (MIW); strike warfare; and surface warfare (SUW). Most activities addressed in the MITT Study Area are categorized under one of the primary mission areas. Activities that do not fall within one of these areas are listed as “other activities.” Each warfare community (surface, subsurface, aviation, and expeditionary warfare) may train in some or all of these primary mission areas. The testing community also categorizes most, but not all, of its testing activities under these primary mission areas. A description of the sonar, munitions, targets, systems, and other material used during training and testing activities within these primary mission areas is provided in the 2020 MITT FSEIS/OEIS Appendix A (
Training and Testing Activities Descriptions
).
The Navy describes and analyzes the effects of its activities within the 2020 MITT FSEIS/OEIS. In its assessment, the Navy concluded that sonar and other transducers and in-water 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 the various warfare mission areas in which they will be conducted. Those mission areas include the following:
Amphibious warfare (underwater detonations)
ASW (sonar and other transducers, underwater detonations)
MIW (sonar and other transducers, underwater detonations)
SUW (underwater detonations)
Other training and testing activities (sonar and other transducers)
The Navy's training and testing activities in air warfare, electronic warfare, and expeditionary warfare do not involve sonar and other transducers, underwater detonations, or any other stressors that could result in harassment, serious injury, or mortality of marine mammals. Therefore, the activities in air, electronic, and expeditionary warfare areas are not discussed further in this rule, but are analyzed fully in the 2020 MITT FSEIS/OEIS. Additional detail regarding the primary mission areas was provided in our
Federal Register
notice of proposed rulemaking (85 FR 5782; January 31, 2020); please see that notice of proposed rulemaking or the Navy's application for more information.
Overview of Major Training Activities and Exercises Within the MITT Study Area
A major training exercise (MTE) for purposes of this rulemaking is comprised of several unit-level activities conducted by several units operating together, commanded and controlled by a single Commander, and typically generating more than 100 hours of active sonar. These exercises typically employ an exercise scenario developed to train and evaluate the exercise participants in tactical and operational tasks. In an MTE, most of the activities being directed and coordinated by the Commander in charge of the exercise are identical in nature to the activities conducted during individual, crew, and smaller unit-level training events. In an MTE, however, these disparate training tasks are conducted in concert, rather than in isolation.
Exercises may also be categorized as integrated or coordinated ASW exercises. The distinction between integrated and coordinated ASW exercises is how the units are being controlled. Integrated ASW exercises are controlled by an existing command structure, and generally occur during the Integrated Phase of the training cycle. Coordinated exercises may have a command structure stood up solely for the event; for example, the commanding officer of a ship may be placed in tactical command of other ships for the duration of the exercise. Not all integrated ASW exercises are considered MTEs, due to their scale, number of participants, duration, and amount of active sonar. The distinction between large, medium, and small integrated or coordinated exercises is based on the scale of the exercise
(i.e.,
number of ASW units participating), the length of the exercise, and the total number of active sonar hours. NMFS considered the effects of all training exercises, not just these major, integrated, and coordinated training exercises in this rule.
Overview of Testing Activities Within the MITT Study Area
The Navy's research and acquisition community engages in a broad spectrum of testing activities in support of the Fleet. These activities include, but are not limited to, basic and applied scientific research and technology development; testing, evaluation, and maintenance of systems (missiles, radar, and sonar) and platforms (surface ships, submarines, and aircraft); and acquisition of systems and platforms. The individual commands within the research and acquisition community include Naval Air Systems Command, Naval Sea Systems Command, and Office of Naval Research.
Description of Stressors
The Navy uses a variety of sensors, 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 the acoustic and explosive stressors for marine mammals and their habitat (including prey species) within the MITT 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 MITT Study Area. Stressor/resource interactions that were determined to have de minimis or no impacts (
i.e.,
vessel, aircraft, or weapons noise, and explosions in air) were 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 acoustic signals emitted into the water for a specific purpose, such as sonar and other transducers (devices that convert energy from one form to another—in this case, into sound waves), as well as 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. Characteristics of each of these sound sources are described in the following sections.
In order to better organize and facilitate the analysis of approximately 300 sources of underwater sound 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. 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:
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;”
Improves efficiency of source utilization data collection and reporting requirements anticipated under the MMPA authorizations;
Ensures a conservative approach to all impact estimates, as all sources within a given class are modeled as the most impactful source (highest source level, longest duty cycle, or largest net explosive weight) within that bin;
Allows analyses to be conducted in a more efficient manner, without any compromise of analytical results; and
Provides a framework to support the reallocation of source usage (hours/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.
Sonar and Other Transducers
Active sonar and other transducers emit non-impulsive sound waves into the water to detect objects, navigate safely, and communicate. Passive sonars differ from active sound sources in that they do not emit acoustic signals; rather, they only receive acoustic information about the environment, or listen. In this rule, the terms sonar and other transducers will be used to indicate active sound sources unless otherwise specified.
The Navy employs a variety of sonars and other transducers to obtain and transmit information about the undersea environment. Some examples are mid-frequency hull-mounted sonars used to find and track enemy submarines; high-frequency small object detection sonars used to detect mines; high-frequency underwater modems used to transfer data over short ranges; and extremely high-frequency (greater than 200 kilohertz (kHz)) doppler sonars used for navigation, like those used on commercial and private vessels. The characteristics of these sonars and other transducers, such as source level, beam width, directivity, and frequency, depend on the purpose of the source. Higher frequencies can carry more information or provide more information about objects off which they reflect, but attenuate more rapidly. Lower frequencies attenuate less rapidly, so may detect objects over a longer distance, but with less detail.
Additional detail regarding sound sources and platforms and categories of acoustic stressors was provided in our
Federal Register
notice of proposed rulemaking (85 FR 5782; January 31, 2020); please see that notice of proposed rulemaking or the Navy's application for more information.
Sonars and other transducers are grouped into classes that share an attribute, such as frequency range or purpose of use. As detailed below, classes are further sorted by bins based on the frequency or bandwidth; source level; and, when warranted, the application in which the source would be used. Unless stated otherwise, a reference distance of 1 meter (m) is used for sonar and other transducers.
• Frequency of the non-impulsive acoustic source;
○ Low-frequency sources operate below 1 kHz;
○ Mid-frequency sources operate at and above 1 kHz, up to and including 10 kHz;
○ High-frequency sources operate above 10 kHz, up to and including 100 kHz;
○ Very high-frequency sources operate above 100 kHz but below 200 kHz;
• Sound pressure level of the non-impulsive source;
○ Greater than 160 decibels (dB) re 1 micro Pascal (μPa), but less than 180 dB re 1 μPa;
○ Equal to 180 dB re 1 μPa and up to 200 dB re 1 μPa;
○ Greater than 200 dB re 1 μPa;
• Application in which the source would be used;
○ Sources with similar functions that have similar characteristics, such as pulse length (duration of each pulse), beam pattern, and duty cycle.
The bins used for classifying active sonars and transducers that are quantitatively analyzed in the MITT Study Area are shown in Table 1 below. While general parameters or source characteristics are shown in the table, actual source parameters are classified.
Table 1—Sonar and Transducers Quantitatively Analyzed in the MITT Study Area
Source class category
Bin
Description
Low-Frequency (LF): Sources that produce signals less than 1 kHz
LF4
LF5
LF sources equal to 180 dB and up to 200 dB.
LF sources less than 180 dB.
Mid-Frequency (MF): Tactical and non-tactical sources that produce signals between 1 and 10 kHz
MF1
Hull-mounted surface ship sonars (
e.g.,
AN/SQS-53C and AN/SQS-60).
MF1K
Kingfisher mode associated with MF1 sonars.
MF3
Hull-mounted submarine sonars (
e.g.,
AN/BQQ-10).
MF4
Helicopter-deployed dipping sonars (
e.g.,
AN/AQS-22).
MF5
Active acoustic sonobuoys (
e.g.,
DICASS).
MF6
Underwater sound signal devices (
e.g.,
MK 84 SUS).
MF9
Sources (equal to 180 dB and up to 200 dB) not otherwise binned.
MF11
Hull-mounted surface ship sonars with an active duty cycle greater than 80 percent.
MF12
Towed array surface ship sonars with an active duty cycle greater than 80 percent.
High-Frequency (HF): Tactical and non-tactical sources that produce signals between 10 and 100 kHz
HF1
HF3
Hull-mounted submarine sonars (
e.g.,
AN/BQQ-10).
Other hull-mounted submarine sonars (classified).
HF4
Mine detection, classification, and neutralization sonar (
e.g.,
AN/SQS-20).
HF6
Sources (equal to 180 dB and up to 200 dB) not otherwise binned.
Anti-Submarine Warfare (ASW): Tactical sources (
e.g.,
active sonobuoys and acoustic countermeasures systems) used during ASW training and testing activities
ASW1
ASW2
MF systems operating above 200 dB.
MF Multistatic Active Coherent sonobuoy (
e.g.,
AN/SSQ-125).
ASW3
MF towed active acoustic countermeasure systems (
e.g.,
AN/SLQ-25).
ASW4
MF expendable active acoustic device countermeasures (
e.g.,
MK 3).
ASW5
MF sonobuoys with high duty cycles.
Torpedoes (TORP): Active acoustic signals produced by torpedoes
TORP1
Lightweight torpedo (
e.g.,
MK 46, MK 54, or Anti-Torpedo Torpedo).
TORP2
Heavyweight torpedo (
e.g.,
MK 48).
TORP3
Heavyweight torpedo (
e.g.,
MK 48).
Forward Looking Sonar (FLS): Forward or upward looking object avoidance sonars used for ship navigation and safety
FLS2
HF sources with short pulse lengths, narrow beam widths, and focused beam patterns.
Acoustic Modems (M): Sources used to transmit data
M3
MF acoustic modems (greater than 190 dB).
Synthetic Aperture Sonars (SAS): Sonars used to form high-resolution images of the seafloor
SAS2
SAS4
HF SAS systems.
MF to HF broadband mine countermeasure sonar.
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 (
Training and Testing Activities Descriptions
) of the 2020 MITT FSEIS/OEIS. Explanations of the terminology and metrics used when describing explosives in the Navy's rule making/LOA application are also in Appendix H (
Acoustic and Explosive Concepts
) of the 2020 MITT FSEIS/OEIS.
The near-instantaneous rise from ambient to an extremely high peak pressure is what makes an explosive shock wave potentially damaging. Farther from an explosive, the peak pressures decay and the explosive waves propagate as an impulsive, broadband sound. Several parameters influence the effect of an explosive: The weight of the explosive in the warhead, the type of explosive material, the boundaries and characteristics of the propagation medium, and, in water, the detonation depth and the depth of the receiver (
i.e.,
marine mammal). The net explosive weight, which is the explosive power of a charge expressed as the equivalent weight of trinitrotoluene (TNT), accounts for the first two parameters. The effects of these factors are explained in Appendix H (
Acoustic and Explosive Concepts
) of the 2020 MITT FSEIS/OEIS.
Explosive detonations during training and testing activities are associated with high-explosive munitions, including, but not limited to, bombs, missiles, rockets, naval gun shells, torpedoes, mines, demolition charges, and explosive sonobuoys. Explosive detonations during training and testing involving the use of high-explosive munitions (including bombs, missiles, and naval gun shells) could occur in the air or at the water's surface. Explosive detonations associated with torpedoes and explosive sonobuoys could occur in the water column; mines and demolition charges could be detonated in the water column or on the ocean bottom. Most detonations will occur in waters greater than 200 ft in depth, and greater than 3 nmi from shore, with the exception of three existing mine warfare areas (Outer Apra Harbor, Piti, and Agat Bay). Nearshore small explosive charges only occur at the three mine warfare areas. Piti and Agat Bay, while nearshore, are in very deep water and used for floating mine neutralization activities. In order to better organize and facilitate the analysis of explosives used by the Navy during training and testing that could detonate in water or at the water surface, explosive classification bins were developed. The use of explosive classification bins provides the same benefits as described for acoustic source classification bins discussed above and in Section 1.4.1 (Acoustic Stressors) of the Navy's rulemaking/LOA application.
Explosives detonated in water are binned by net explosive weight. The bins of explosives that are planned for use in the MITT Study Area are shown in Table 2 below.
Table 2—Explosives Analyzed in the MITT Study Area
Bin
Net
explosive
weight
(lb)
Example explosive source
E1
0.1-0.25
Medium-caliber projectiles.
E2
>0.25-0.5
Anti-swimmer grenade.
E3
>0.5-2.5
57 mm projectile.
E4
>2.5-5
Mine neutralization charge.
E5
>5-10
5 in projectiles.
E6
>10-20
Hellfire missile.
E8
>60-100
250 lb bomb; Lightweight torpedo.
E9
>100-250
500 lb bomb.
E10
>250-500
1,000 lb bomb.
E11
>500-650
Heavyweight torpedo.
E12
>650-1,000
2,000 lb bomb.
Notes:
(1) Net Explosive Weight refers to the equivalent amount of TNT. The actual weight of a munition may be larger due to other components; (2) in = inch(es), lb = pound(s), ft = feet.
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. Appendix H (
Acoustic and Explosive Concepts
) of the 2020 MITT FSEIS/OEIS explains the characteristics of explosive detonations and how the above factors affect the propagation of explosive energy in the water.
Marine mammals could be exposed to fragments from underwater explosions associated with the specified activities. When explosive ordnance
(e.g.,
bomb or missile) detonates, fragments of the weapon are thrown at high-velocity from the detonation point, which can injure or kill marine mammals if they are struck. These fragments may be of variable size and are ejected at supersonic speed from the detonation. The casing fragments will be ejected at velocities much greater than debris from any target due to the proximity of the casing to the explosive material. Risk of fragment injury reduces exponentially with distance as the fragment density is reduced. Fragments underwater tend to be larger than fragments produced by in-air explosions (Swisdak and Montaro, 1992). Underwater, the friction of the water would quickly slow these fragments to a point where they no longer pose a threat. Opposingly, the blast wave from an explosive detonation moves efficiently through the seawater. Because the ranges to mortality and injury due to exposure to the blast wave are likely to far exceed the zone where fragments could injure or kill an animal, the thresholds for assessing the likelihood of harassment from a blast, which are also used to inform mitigation zones, are assumed to encompass risk due to fragmentation.
Detailed Description of the Specified Activities
Planned Training and Testing Activities
The Navy's Operational Commands and various System Commands have identified activity levels that are needed in the MITT Study Area to ensure naval forces have sufficient training, maintenance, and new technology to meet Navy missions in the Pacific. Training prepares Navy personnel to be proficient in safely operating and maintaining equipment, weapons, and systems to conduct assigned missions. Navy research develops new science and technology followed by concept testing relevant to future Navy needs. Unlike other Navy range complexes, training and testing in the MITT Study Area is more episodic as transiting strike groups or individual units travel through on the way to and from the Western Pacific, or forward deployed assets temporarily travel to the MITT Study Area for individual or group activities. This section analyzes a maximum number of activities that could occur each year and then a maximum total of activities that could occur over seven years. One activity, Torpedo (Explosive) Testing, does not occur every year, but the maximum times it could occur over one year and seven years was analyzed.
The training and testing activities that the Navy proposes to conduct in the MITT Study Area are summarized in Table 3. The table is organized according to primary mission areas and includes the activity name, associated stressors, description of the activity, sound source bin, the locations of those activities in the MITT Study Area, and the number of activities. For further information regarding the primary platform used (
e.g.,
ship or aircraft type) see Appendix A (
Training and Testing Activities Descriptions
) of the 2020 MITT FSEIS/OEIS.
Table 3—Training and Testing Activities Analyzed Annually and for a Seven-Year Period in the MITT Study Area
Stressor category
Activity
Description
Typical duration of event
Source bin
1
Location
Annual number of events
7-Year number of events
Major Training Event—Large Integrated Anti-Submarine Warfare Training (ASW)
Acoustic
Joint Multi-Strike Group Exercise
Typically a 10-day Joint exercise, in which up to three carrier strike groups would conduct training exercises simultaneously
10 days
ASW2, ASW3, ASW4, ASW5, HF1, MF1, MF11, MF3, MF4, MF5, MF12, TORP1
Study Area; MIRC
1
7
Major Training Event—Medium Integrated ASW
Acoustic
Joint Expeditionary Exercise
Typically a 10-day exercise that could include a Carrier Strike Group and Expeditionary Strike Group, Marine Expeditionary Units, Army Infantry Units, and Air Force aircraft together in a joint environment that includes planning and execution efforts as well as military training activities at sea, in the air, and ashore
10 days
ASW2, ASW3, MF1, MF4, MF5, MF12
Study Area; Apra Harbor
1
7
Medium Coordinated ASW
Acoustic
Marine Air Ground Task Force Exercise (Amphibious)—Battalion
Typically a 10-day exercise that conducts over the horizon, ship to objective maneuver for the elements of the Expeditionary Strike Group and the Amphibious Marine Air Ground Task Force. The exercise utilizes all elements of the Marine Air Ground Task Force (Amphibious), conducting training activities ashore with logistic support of the Expeditionary Strike Group and conducting amphibious landings
10 days
ASW3, MF1, MF4, MF12
Study Area to nearshore; MIRC; Tinian; Guam; Rota; Saipan; Farallon De Medinilla
4
28
ASW
Acoustic
Tracking Exercise—Helicopter (TRACKEX—Helo)
Helicopter crews search for, detect, and track submarines
2-4 hours
MF4, MF5
Study Area >3 NM from land; Transit Corridor
10
70
Acoustic
Torpedo Exercise—Helicopter (TORPEX—Helo)
Helicopter crews search for, detect, and track submarines. Recoverable air launched torpedoes are employed against submarine targets
2-5 hours
MF4, MF5, TORP1
Study Area >3 NM from land
6
42
Acoustic
Tracking Exercise—Maritime Patrol Aircraft (TRACKEX—Maritime Patrol Aircraft)
Maritime patrol aircraft crews search for, detect, and track submarines
2-8 hours
MF5
Study Area >3 NM from land
36
252
Acoustic
Torpedo Exercise—Maritime Patrol Aircraft (TORPEX—Maritime Patrol Aircraft)
Maritime patrol aircraft crews search for, detect, and track submarines. Recoverable air launched torpedoes are employed against submarine targets
2-8 hours
MF5, TORP1
Study Area >3 NM from land
6
42
Acoustic
Tracking Exercise -Surface (TRACKEX—Surface)
Surface ship crews search for, detect, and track submarines
2-4 hours
ASW1, ASW3, MF1, MF11, MF12
Study Area >3 NM from land*
91
637
Acoustic
Torpedo Exercise—Surface (TORPEX—Surface)
Surface ship crews search for, detect, and track submarines. Exercise torpedoes are used during this event
2-5 hours
ASW3, MF1, MF5, TORP1
Study Area >3 NM from land
6
42
Acoustic
Tracking Exercise—Submarine (TRACKEX—Sub)
Submarine crews search for, detect, and track submarines
8 hours
ASW4, HF1, HF3, MF3
Study Area >3 NM from land; Transit Corridor
4
28
Acoustic
Torpedo Exercise—Submarine (TORPEX—Sub)
Submarine crews search for, detect, and track submarines. Recoverable exercise torpedoes are used during this event
8 hours
ASW4, HF1, MF3, TORP2
Study Area >3 NM from land
9
63
Acoustic
Small Combined Coordinated ASW exercise (Multi-Sail/GUAMEX)
Typically, a 5-day exercise with multiple ships, aircraft and submarines integrating the use of their sensors, including sonobuoys, to search, detect, and track threat submarines
5 days
ASW2, ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, MF11, MF12
Study Area >3 NM from land*
38
56
Mine Warfare
Acoustic
Civilian Port Defense
Maritime security personnel train to protect civilian ports and harbors against enemy efforts to interfere with access to those ports
Multiple days
HF4, SAS2
MIRC, Mariana littorals, Inner and Outer Apra Harbor
1
7
Explosive
Mine Neutralization—Remotely Operated Vehicle Sonar (ASQ-235 [AQS-20], SLQ-48)
Ship, small boat, and helicopter crews locate and disable mines using remotely operated underwater vehicles
1-4 hours
E4
Study Area, Mariana littorals, and Outer Apra Harbor
4
28
Acoustic
Mine Countermeasure Exercise—Surface Ship Sonar (SQQ-32, MCM)
Ship crews detect, locate, identify, and avoid mines while navigating restricted areas or channels, such as while entering or leaving port
1-4 hours
HF4
Study Area, Apra Harbor
4
28
Acoustic
Mine Countermeasure Exercise—Towed Sonar (AQS-20)
Surface ship crews detect and avoid mines while navigating restricted areas or channels using towed active sonar systems
1-4 hours
HF4
Study Area, Apra Harbor
4
28
Explosive
Mine Neutralization—Explosive Ordnance Disposal
Personnel disable threat mines using explosive charges
Up to 4 hours
E5, E6
Agat Bay site, Piti, and Outer Apra Harbor
20
140
Acoustic
Submarine Mine Exercise
Submarine crews practice detecting mines in a designated area
Varies
HF1
Study Area, Mariana Littorals, Inner/Outer Apra Harbor
1
7
Acoustic
Surface Ship Object Detection
Ship crews detect and avoid mines while navigating restricted areas or channels using active sonar
1-4 hours
MF1K
Study Area
6
42
Explosive
Underwater Demolition Qualification/Certification
Navy divers conduct various levels of training and certification in placing underwater demolition charges
Varies
E5, E6
Agat Bay site, Piti, and Outer Apra Harbor
45
315
Surface Warfare (SUW)
Explosive
Bombing Exercise (Air-to-Surface)
Fixed-wing aircrews deliver bombs against stationary surface targets
1 hour
E9, E10, E12
Study Area, Special Use Airspace
37
259
Explosive
Gunnery Exercise (GUNEX) (Air-to-Surface)—Medium-caliber
Fixed-wing and helicopter aircrews fire medium-caliber guns at surface targets
1 hour
E1, E2
Study Area >12 NM from land, Special Use Airspace
120
840
Explosive
GUNEX (Surface-to-Surface) Boat—Medium-caliber
Small boat crews fire medium-caliber guns at surface targets
1 hour
E2
Study Area >12 NM from land, Special Use Airspace
20
140
Explosive
GUNEX (Surface-to-Surface) Ship—Large-caliber
Surface ship crews fire large-caliber guns at surface targets
Up to 3 hours
E5
Study Area >12 NM from land, Special Use Airspace
255
1,785
Explosive
GUNEX (Surface-to-Surface) Ship—Small- and Medium-caliber
Surface ship crews fire medium and small-caliber guns at surface targets
2-3 hours
E1
Study Area >12 NM from land, Special Use Airspace
234
1,638
Explosive
Maritime Security Operations
Helicopter, surface ship, and small boat crews conduct a suite of maritime security operations at sea, to include visit, board, search and seizure, maritime interdiction operations, force protection, and anti-piracy operations
Up to 3 hours
E2
Study Area; MIRC
40
280
Explosive
Missile Exercise (Air-to-Surface) (MISSILEX [A-S])
Fixed-wing and helicopter aircrews fire air-to-surface missiles at surface targets
2 hours
E6, E8, E10
Study Area >12 NM from land, Special Use Airspace
10
70
Explosive
Missile Exercise (Air-to-Surface)—Rocket (MISSILEX [A-S]—Rocket)
Helicopter aircrews fire both precision-guided and unguided rockets at surface targets
1 hour
E3
Study Area >12 NM from land, Special Use Airspace
110
770
Explosive
Missile Exercise (Surface-to-Surface)
(MISSILEX [S-S])
Surface ship crews defend against surface threats (ships or small boats) and engage them with missiles
2-5 hours
E6, E10
Study Area >50 NM from land, Special Use Airspace
28
196
Explosive
Sinking Exercise
Aircraft, ship, and submarine crews deliberately sink a seaborne target, usually a decommissioned ship made environmentally safe for sinking according to U.S. Environmental Protection Agency standards, with a variety of ordnance
4-8 hours, possibly over 1-2 days
E5, E8, E10, E11, E12, TORP2
Study Area >50 NM from land and >1,000 fathoms depth
1
7
Other Training Activities
Acoustic
Submarine Navigation
Submarine crews operate sonar for navigation and detection while transiting into and out of port during reduced visibility
Up to 2 hours
HF1, MF3
Study Area, Apra Harbor, and Mariana littorals
8
56
Acoustic
Submarine Sonar Maintenance
Maintenance of submarine sonar and other system checks are conducted pierside or at sea
Up to 1 hour
MF3
Study Area; Apra Harbor and Mariana littorals
86
602
Acoustic
Surface Ship Sonar Maintenance
Maintenance of surface ship sonar and other system checks are conducted pierside or at sea
Up to 4 hours
MF1
Study Area; Apra Harbor and Mariana littorals
44
308
Acoustic
Unmanned Underwater Vehicle Training
Units conduct training with unmanned underwater vehicles from a variety of platforms, including surface ships, small boats, and submarines
Up to 24 hours
FLS2, M3, SAS2, SAS4
MIRC; Apra Harbor and Mariana littorals
64
448
Testing Activities
ASW
Acoustic; Explosive
Anti-Submarine Warfare Tracking Test—Maritime Patrol Aircraft (Sonobuoys)
The test evaluates the sensors and systems used by maritime patrol aircraft to detect and track submarines and to ensure that aircraft systems used to deploy the tracking systems perform to specifications and meet operational requirements
8 hours
ASW2, ASW5, E1, E3, MF5, MF6
Study Area >3 NM from land
26
182
Acoustic
Anti-Submarine Warfare Torpedo Test
This event is similar to the training event torpedo exercise. Test evaluates anti-submarine warfare systems onboard rotary-wing and fixed-wing aircraft and the ability to search for, detect, classify, localize, track, and attack a submarine or similar target
2-6 flight hours
MF5, TORP1
Study Area >3 NM from land
20
140
Acoustic
Anti-Submarine Warfare Mission Package Testing
Ships and their supporting platforms (
e.g.,
helicopters and unmanned aerial systems) detect, localize, and prosecute submarines
1-2 weeks, with 4-8 hours of active sonar use with intervals of non-activity in between
ASW1, ASW2, ASW3, ASW5, MF12, MF4, MF5, TORP1
Mariana Island Range Complex
100
700
Acoustic
At-Sea Sonar Testing
At-sea testing to ensure systems are fully functional in an open ocean environment
From 4 hours to 11 days
HF1, HF6, M3, MF3, MF9
Study Area
7
49
Acoustic; Explosive
Torpedo (Explosive) Testing
Air, surface, or submarine crews employ explosive and non-explosive torpedoes against artificial targets
1-2 days during daylight hours
ASW3, HF1, HF6, MF1, MF3, MF4, MF5, MF6, TORP1, TORP2, E8, E11
Mariana Island Range Complex
3
9
Acoustic
Torpedo (Non-explosive) Testing
Air, surface, or submarine crews employ non-explosive torpedoes against submarines or surface vessels
Up to 2 weeks
ASW3, ASW4, HF1, HF6, LF4, MF1, MF3, MF4, MF5, MF6, TORP1, TORP2, TORP3
Mariana Island Range Complex
7
49
Mine Warfare
Acoustic; Explosive
Mine Countermeasure and Neutralization Testing
Air, surface, and subsurface vessels neutralize threat mines and mine-like objects
1-10 days, with intermittent use of countermeasure/neutralization systems during this period
HF4, E4
MIRC; nearshore and littorals
3
21
Surface Warfare
Explosive
Air to Surface Missile Test
Fixed-wing and helicopter aircrews fire air-to-surface missiles at surface targets
2 hours
E10
Study Area >50 NM from land
4
28
Vessel Evaluation
Acoustic
Undersea Warfare Testing
Ships demonstrate capability of countermeasure systems and underwater surveillance, weapons engagement, and communications systems. This tests ships' ability to detect, track, and engage undersea targets
Up to 10 days
HF4, MF1, MF4, MF5, TORP1
MIRC
1
7
1
Additional activities utilizing sources not listed in the Major Training Event and coordinated exercise bins above may occur during these exercises. All acoustic sources which may be used during training and testing activities have been accounted for in the modeling and analysis presented in this application and in the 2020 MITT FSEIS/OEIS.
* Includes limited occurrence within the Marpi Reef Geographic Mitigation Area and a portion of Chalan Kanoa Reef Geographic Mitigation Area outside of 3 nmi from land (see Figures 1 and 2).
Summary of Acoustic and Explosive Sources Analyzed for Training and Testing
Tables 4 and 5 show the acoustic and explosive source classes, bins, and quantities used in either hours or counts associated with the Navy's training and testing activities over a seven-year period in the MITT Study Area that were analyzed in the Navy's rulemaking/LOA application. Table 4 describes the acoustic source classes (
i.e.,
low-frequency (LF), mid-frequency (MF), and high-frequency (HF)) that could occur over seven years under the planned training and testing activities. Acoustic source bin use in the planned activities will vary annually. The seven-year totals for the planned training and testing activities take into account that annual variability.
Table 4—Acoustic Source Classes Analyzed and Number Used for a Seven-Year Period for Training and Testing activities in the MITT Study Area
Source class category
Bin
Description
Unit
Annual
7-year total
Low-Frequency (LF): Sources that produce signals less than 1 kHz
LF4
LF sources equal to 180 dB and up to 200 dB
H
1
7
LF5
LF sources less than 180 dB
H
10
65
Mid-Frequency (MF): Tactical and non-tactical sources that produce signals between 1 and 10 kHz
MF1
Hull-mounted surface ship sonars (
e.g.,
AN/SQS-53C and AN/SQS-60)
H
1,818
12,725
MF1K
Kingfisher mode associated with MF1 sonars
H
3
21
MF3
Hull-mounted submarine sonars (
e.g.,
AN/BQQ-10)
H
227
1,586
MF4
Helicopter-deployed dipping sonars (
e.g.,
AN/AQS-22)
H
185
1,289
MF5
Active acoustic sonobuoys (
e.g.,
DICASS)
C
2,094
14,623
MF6
Active underwater sound signal devices (
e.g.,
MK 84 SUS)
C
74
458
MF9
Active sources (equal to 180 dB and up to
200 dB) not otherwise binned
H
29
202
MF11
Hull-mounted surface ship sonars with an active duty cycle greater than 80%
H
304
2.128
MF12
Towed array surface ship sonars with an active duty cycle greater than 80%
H
616
4,320
High-Frequency (HF): Tactical and non-tactical sources that produce signals between 10 and 100 kHz
HF1
Hull-mounted submarine sonars (
e.g.,
AN/BQQ-10)
H
73
497
HF3
Other hull-mounted submarine sonars (classified)
H
4
28
HF4
Mine detection, classification, and neutralization sonar (
e.g.,
AN/SQS-20)
H
1,472
10,304
HF6
Active sources (equal to 180 dB and up to 200 dB) not otherwise binned
H
309
2,128
Anti-Submarine Warfare (ASW): Tactical sources (
e.g.,
active sonobuoys and acoustic countermeasures systems) used during ASW training and testing activities
ASW1
MF systems operating above 200 dB
H
192
1,360
ASW2
MF Multistatic Active Coherent sonobuoy (
e.g.,
AN/SSQ-125)
C
554
3,878
ASW3
MF towed active acoustic countermeasure systems (
e.g.,
AN/SLQ-25)
H
3,124
21,863
ASW4
MF expendable active acoustic device countermeasures (
e.g.,
MK 3)
C
332
2,324
ASW5
MF sonobuoys with high duty cycles
H
50
350
Torpedoes (TORP): Source classes associated with the active acoustic signals produced by torpedoes
TORP1
Lightweight torpedo (
e.g.,
MK 46, MK 54, or Anti-Torpedo Torpedo)
C
71
485
TORP2
Heavyweight torpedo (
e.g.,
MK 48)
C
62
398
TORP3
Heavyweight torpedo test (
e.g.,
MK 48)
C
6
42
Forward Looking Sonar (FLS): Forward or upward looking object avoidance sonars used for ship navigation and safety
FLS2
HF sources with short pulse lengths, narrow beam widths, and focused beam patterns
H
4
28
Acoustic Modems (M): Systems used to transmit data through the water
M3
MF acoustic modems (greater than 190 dB)
H
31
216
Synthetic Aperture Sonars (SAS): Sonars in which active acoustic signals are post-processed to form high-resolution images of the seafloor
SAS2
HF SAS systems
H
449
3,140
SAS4
MF to HF broadband mine countermeasure sonar
H
6
42
Notes:
H= hours; C = count.
Table 5 describes the number of in-water explosives that could be used in any year under the planned training and testing activities. Under the planned activities, bin use will vary annually, and the seven-year totals for the planned training and testing activities take into account that annual variability.
Table 5—Explosive Source Bins Analyzed and Number Used Annually and for a Seven-Year Period for Training and Testing Activities Within the MITT Study Area
Bin
Net
explosive
weight
(lb)
Example Explosive Source
Annual
7-year total
E1
0.1-0.25
Medium-caliber projectiles
768
5,376
E2
>0.25-0.5
Anti-swimmer grenade
400
2,800
E3
>0.5-2.5
57 mm projectile
683
4,591
E4
>2.5-5
Mine neutralization charge
44
308
E5
>5-10
5 in projectiles
1,221
8,547
E6
>10-20
15 lb shaped charge
29
203
E8
>60-100
250 lb bomb; Light weight torpedo
134
932
E9
>100-250
500 lb bomb
110
770
E10
>250-500
1,000 lb bomb
78
546
E11
>500-650
Heavy weight torpedo
5
17
E12
>650-1,000
2,000 lb bomb
48
336
Notes:
(1) net explosive weight refers to the equivalent amount of TNT. The actual weight of a munition may be larger due to other components. (2) in = inch(es), lb = pound(s), ft = feet.
Vessel Movement
The only areas with projected high concentrations of Navy vessel movement will be within Apra Harbor Guam and the coastal approaches to and from Apra Harbor. Some amphibious training events use Tinian as a landing area so amphibious ships could occur in the offshore waters off that island. Most other activities are spread throughout the greater MITT Study Area with a high degree of spatial and temporal separation between activities. Additional detail on vessel movement was provided in our
Federal Register
notice of proposed rulemaking (85 FR 5782; January 31, 2020); please see that notice of proposed rulemaking or the
Navy's application for more information.
The Navy tabulated annual at-sea vessel steaming days for training and testing activities projected for the MITT Study Area. Across all warfare areas and activities, 493 days of Navy at-sea time will occur annually for training and testing activities in the MITT Study Area (Table 6). Amphibious Warfare activities account for 48 percent of total surface ship days, MTEs account for 38 percent, ASW activities account for 8 percent, and Air Warfare, ASW, and Other activities (sonar maintenance, anchoring) account for 2 percent each (Table 6). In comparison to the Hawaii-Southern California Training and Testing (HSTT) Study Area, the estimated number of at-sea annual days for training and testing activities in the MITT Study Area is approximately ten times less than in the HSTT Study Area over the same time period.
Table 6—Annual Navy Surface Ship Days Within the MITT Study Area
MITT events
Annual days
Percent
by event
Annual days
by warfare
area
Percent by
warfare area
Air Warfare
9
1.9
GUNNEX (Lg)
2
0.3
GUNNEX (Sm)
3
0.6
MISSILEX
5
0.9
Amphibious Warfare
299
60.7
Fire Support (Land Target)
5
1.0
Amphibious Rehearsal
144
29.2
Amphibious Assault
14
2.8
Amphibious Raid
3
0.6
Marine Air Ground Task Force Exercise
40
8.1
Non-Combatant Evacuation Op
67
13.5
Humanitarian Assist/Disaster Relief Op
7
1.4
Special Purpose
Marine Air Ground Task Force Exercise
20
4.1
Surface Warfare
41
8.4
MISSILEX
2
0.4
GUNNEX (Lg)
14
2.8
GUNNEX (Med)
10
2.0
GUNNEX (Sm)
6
1.3
SINKEX
7
1.4
Maritime Security Op
3
0.5
Anti-Submarine Warfare
8
1.6
Tracking Exercise
8
1.5
Torpedo Exercise
1
0.1
Major Training Exercises
125
24.5
Joint Expeditionary Exercise
63
12.9
Joint Multi-Strike Group Exercise
62
12.5
Other
10
2.1
Surface Ship Sonar Maintenance
7
1.5%
Precision Anchoring
3
0.6%
Total
493
Additional details on Navy at-sea vessel movement are provided in the 2020 MITT FSEIS/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. While standard operating procedures are designed for the safety of personnel and equipment and to ensure the success of training and testing activities, their implementation often yields additional benefits on environmental, socioeconomic, public health and safety, and cultural resources.
Because standard operating procedures are essential to safety and mission success, the Navy considers them to be part of the planned Specified Activities, and has included them in the environmental analysis. Additional details on standard operating procedures were provided in our
Federal Register
notice of proposed rulemaking (85 FR 5782; January 31, 2020); please see that notice of proposed rulemaking or the Navy's application for more information.
Comments and Responses
We published the proposed rule in the
Federal Register
on January 31, 2020 (85 FR 5782), with a 45-day comment period. With that proposed rule, we requested public input on our analyses, our preliminary findings, and the proposed regulations, and requested that interested persons submit relevant information and comments. During the 45-day comment period, we received 16 comment letters in total. Of this total, one submission was from another Federal agency, one was from the Marine Mammal Commission, three letters were from organizations or individuals acting in an official capacity (
e.g.,
non-governmental organizations (NGOs), and 11 submissions were from private citizens. NMFS has reviewed and considered all public comments received on the proposed rule and issuance of the LOA. General comments that did not provide information pertinent to NMFS' decisions have been noted, but are not addressed further. All substantive comments and our responses are described below. We provide no response to specific comments that addressed species or statutes not relevant to the rulemaking under section 101(a)(5)(A) of the MMPA (
e.g.,
comments related to sea turtles). We organize our comment responses by major categories.
General Comments
Comment 1:
The Navy must be required to submit a Habitat Conservation Plan that will ensure the well being of those mammals to the best extent possible.
Response:
A Habitat Conservation Plan (HCP) is a planning document for non-Federal agencies and persons to obtain an ESA incidental take permit under section 10(a)(1)(B) of the Endangered Species Act (ESA). The Navy is a Federal agency that consulted with NMFS under section 7 of the ESA, and therefore obtaining a separate ESA incidental take permit is not required. The Navy will comply with the Reasonable and Prudent Measures and Terms and Conditions that are part of their Incidental Take Statement, which was issued as part of the consultation process under section 7 of the ESA.
Impact Analysis and Thresholds
Comment 2:
A commenter recommended that NMFS clarify whether and how the Navy incorporated uncertainty in its density estimates for its animat modeling specific to MITT and if uncertainty was not incorporated, re-estimate the numbers of marine mammal takes based on the uncertainty inherent in the density estimates provided in Department of the Navy (2018b).
Response:
Uncertainty was incorporated into the density estimates used for modeling and estimating take for NMFS' rule. The commenter is referred to the technical report titled “Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing” (U.S. Department of the Navy, 2018) for clarification on the consideration of uncertainty in density estimates. See specifically Section 4.2 (Marine Species Distribution Builder) of the 2020 MITT FSEIS/OEIS where details are provided on how statistical uncertainty surrounding density estimates was incorporated into the modeling for the MITT Study Area, as has been done for all other recent NMFS and Navy analyses of training and testing at sea. To the Commenters more specific question, as with the 2018 HSTT final rule, a lognormal distribution was used in the density regression model. Uncertainty was incorporated into the take estimation through the density estimates and it is not necessary to re-estimate the take numbers for marine mammals.
Comment 3:
A Commenter stated that NMFS has largely followed the Navy in revising its hearing loss thresholds to reflect certain new data and modeling approaches. The Commenter suggested they have previously advised that the criteria that NMFS produced to estimate temporary and permanent threshold shift in marine mammals are erroneous and non-conservative. According to the Commenter, Wright (2015) has identified several statistical and numerical faults in NMFS' approach, such as pseudo-replication and inconsistent treatment of data, that tend to bias the criteria towards an underestimation of effects. The Commenter stated that similar and additional issues were raised by a dozen scientists during the public comment period on the draft criteria held by NMFS. The Commenter asserts that the issue is NMFS' broad extrapolation from a small number of individual animals, mostly bottlenose dolphins, without taking account of what Racca
et al.
(2015b) have succinctly characterized as a “non-linear accumulation of uncertainty.” The Commenter asserts that NMFS failed to address the basic errors identified by these and other experts, nor did it perform a sensitivity analysis to understand the potential magnitude of those errors. The Commenter suggests that NMFS should not rely exclusively on its auditory guidance in determining “Level A” take, but should, at minimum, produce a conservative upper bound such as by retaining the 180 dB threshold, or by performing a sensitivity analysis.
Response:
The Acoustic Technical Guidance updates the historical 180 dB rms injury threshold, which was based on professional judgement (
i.e.,
no data were available on the effects of noise on marine mammal hearing at the time this original threshold was derived). NMFS disagrees with any suggestion that the use of the Acoustic Technical Guidance provides erroneous results. The 180 dB rms threshold is plainly outdated, as the best available science indicates that rms SPL is not even an appropriate metric by which to gauge potential auditory injury. Further, NMFS disagrees with the suggestion that NMFS should not rely exclusively on its Technical Guidance in determining take by Level A harassment and should instead also produce an upper bound (either by retaining the 180-dB threshold or performing a sensitivity analysis). The Acoustic Technical Guidance represents the best available science and provides thresholds and weighting functions that allow us to predict when marine mammals are likely to incur permanent threshold shift (PTS). As described in the
Estimated Take of Marine Mammals
section, when the acoustic thresholds, the Navy model, and other inputs into the take calculation are considered, the authorized incidental takes represent the maximum number of instances in which marine mammals are reasonably expected to be taken, which is appropriate under the statute and there is no need or requirement for NMFS to authorize a larger number.
Multiple studies from humans, terrestrial mammals, and marine mammals have demonstrated less temporary threshold shift (TTS) from intermittent exposures compared to continuous exposures with the same total energy because hearing is known to experience some recovery in between noise exposures, which means that the effects of intermittent noise sources such as tactical sonars are likely overestimated. Marine mammal TTS data have also shown that, for two exposures with equal energy, the longer duration exposure tends to produce a larger amount of TTS. Most marine mammal TTS data have been obtained using exposure durations of tens of seconds up to an hour, much longer than the durations of many tactical sources (much less the continuous time that a marine mammal in the field would be exposed consecutively to those levels), further suggesting that the use of these TTS data are likely to overestimate the effects of sonars with shorter duration signals.
Regarding the suggestion of pseudoreplication and erroneous models, since marine mammal hearing and noise-induced hearing loss data are limited, both in the number of species and in the number of individuals available, attempts to minimize pseudoreplication would further reduce these already limited data sets. Specifically, with marine mammal behaviorally derived temporary threshold shift studies, behaviorally derived data are only available for two mid-frequency cetacean species (bottlenose dolphin, beluga) and two phocids (in-water) pinniped species (harbor seal and northern elephant seal), with otariid (in-water) pinnipeds and high-frequency cetaceans only having behaviorally-derived data from one species. Arguments from Wright (2015) regarding pseudoreplication within the TTS data are therefore largely irrelevant in a practical sense because there are so few data. Multiple data points were not included for the same individual at a single frequency. If multiple data existed at one frequency, the lowest TTS onset was always used. There is only a single frequency where TTS onset data exist for two individuals of the same species: 3 kHz for bottlenose dolphins. Their TTS (unweighted) onset values
were 193 and 194 dB re 1 μPa2s. Thus, NMFS believes that the current approach makes the best use of the given data. Appropriate means of reducing pseudoreplication may be considered in the future, if more data become available. Many other comments from Wright (2015) and the comments from Racca
et al.
(2015b) appear to be erroneously based on the idea that the shapes of the auditory weighting functions and TTS/PTS exposure thresholds are directly related to the audiograms;
i.e.,
that changes to the composite audiograms would directly influence the TTS/PTS exposure functions (
e.g.,
Wright (2015) describes weighting functions as “effectively the mirror image of an audiogram” (p. 2) and states, “The underlying goal was to estimate how much a sound level needs to be above hearing threshold to induce TTS.” (p. 3)). Both statements are incorrect and suggest a fundamental misunderstanding of the criteria/threshold derivation. This would require a constant (frequency-independent) relationship between hearing threshold and TTS onset that is not reflected in the actual marine mammal TTS data. Attempts to create a “cautionary” outcome by artificially lowering the composite audiogram thresholds would not necessarily result in lower TTS/PTS exposure levels, since the exposure functions are to a large extent based on applying mathematical functions to fit the existing TTS data.
Comment 4:
A Commenter recommended that NMFS specify in the preamble to the final rule whether the data regarding behavioral audiograms (Branstetter
et al.
2017, Kastelein
et al.
2017b) and TTS (Kastelein
et al.
2017a and c, Popov
et al.
2017, Kastelein
et al.
2018a and 2019a and b) support the continued use of the current weighting functions and PTS and TTS thresholds.
Response:
Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of this rule regarding current weighting functions and PTS and TTS thresholds. Furthermore, the recent peer-reviewed updated marine mammal noise exposure criteria by Southall
et al.
(2019a) provide identical PTS and TTS thresholds to those provided in NMFS' Acoustic Technical Guidance. NMFS' Revised Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2018) (Acoustic Technical Guidance), which was used in the assessment of effects for this rulemaking, compiled, interpreted, and synthesized the best available scientific information for noise-induced hearing effects for marine mammals to derive updated thresholds for assessing the impacts of noise on marine mammal hearing, including the articles that the Commenter referenced that were published subsequent to the publication of the first version of the Acoustic Technical Guidance in 2016. The new data included in those articles are consistent with the thresholds and weighting functions included in the current version of the Acoustic Technical Guidance (NMFS, 2018). NMFS will continue to review and evaluate new relevant data as it becomes available and consider the impacts of those studies on the Acoustic Technical Guidance to determine what revisions/updates may be appropriate.
Comment 5:
Commenters recommended that NMFS refrain from using cut-off distances in conjunction with the Bayesian Behavioral Response Functions (BRFs) and re-estimate the numbers of marine mammal takes based solely on the Bayesian BRFs as the use of cut-off distances could be perceived as an attempt to reduce the numbers of takes.
Response:
The consideration of proximity (cut-off distances) was part of the criteria developed in consultation between the Navy and NMFS, and is appropriate based on the best available science which shows that marine mammal responses to sound vary based on both sound level and distance. Therefore these cut-off distances were applied within the Navy's acoustic effects model. The derivation of the behavioral response functions and associated cut-off distances is provided in the 2017 technical report titled “Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III)”. To account for non-applicable contextual factors, all available data on marine mammal reactions to actual Navy activities and other sound sources (or other large scale activities such as seismic surveys when information on proximity to sonar sources was not available for a given species group) were reviewed to find the farthest distance to which significant behavioral reactions were observed. These distances were rounded up to the nearest 5 or 10 km interval, and for moderate to large scale activities using multiple or louder sonar sources, these distances were greatly increased—doubled in most cases. The Navy's BRFs applied within these distances provide technically sound methods reflective of the best available science to estimate the impact and potential take for the actions analyzed within the 2020 MITT FSEIS/OEIS and included in these regulations. NMFS has independently assessed the Navy's behavioral harassment thresholds (
i.e.,
their BRFs) and finds that they appropriately apply the best available science and it is not necessary to recalculate take estimates.
The Commenters also specifically expressed concern that distance “cut-offs” alleviate some of the exposures that would otherwise have been counted if the received level alone were considered. It is unclear why the Commenters find this inherently inappropriate, as this is what the data show. As noted previously, there are multiple studies illustrating that in situations where one would expect behavioral disturbance of a certain degree because of the received levels at which previous responses were observed, it has not occurred when the distance from the source was larger than the distance of the first observed response.
Comment 6:
Regarding the behavioral harassment thresholds for explosives, Commenters recommended that NMFS estimate and ultimately authorize takes of marine mammals by Level B harassment in the form of behavioral disturbance, as well as TTS, during all explosive activities, including those that involve single detonations.
Response:
The derivation of the explosive injury criteria is provided in the 2017 technical report titled “Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III),” and NMFS has applied the general rule a commenter referenced to single explosives for years,
i.e.,
that marine mammals are unlikely to respond to a single instantaneous detonation
at received levels below the TTS threshold
in a manner that would rise to the level of a take. Neither NMFS nor the Navy are aware of evidence to support the assertion that animals will have significant behavioral reactions
(i.e.,
those that would rise to the level of a take) to temporally and spatially isolated explosions at received levels below the TTS threshold.
Marine mammals may be exposed to isolated impulses in their natural environment (
e.g.,
lightning). There is no evidence to support that animals have significant behavioral responses to temporally and spatially isolated impulses (such as military explosions) that may rise to the level of “harassment” under the MMPA for military readiness activities. Still, the analysis conservatively assumes that any modeled instance of temporally or spatially separated detonations occurring in a single 24-hour period would result in harassment under the
MMPA for military readiness activities. The Navy has been monitoring detonations since the 1990s and has not observed these types of reactions. To be clear, this monitoring has occurred under the monitoring plans developed specifically for shock trials, the detonations with the largest net explosive weight conducted by the Navy, and no shock trials are proposed in this study area.
Further, to clarify, the current take estimate framework does not preclude the consideration of animals being behaviorally disturbed during single explosions as they are counted as “taken by Level B harassment” if they are exposed above the TTS threshold, which is only 5 dB higher than the behavioral harassment threshold. We acknowledge in our analysis that individuals exposed above the TTS threshold may also be behaviorally disturbed and those potential impacts are considered in the negligible impact determination.
Comment 7:
A Commenter stated that the behavioral response functions rely on captive animal studies and the risk functions do not incorporate a number of relevant studies on wild marine mammals (specifically referencing a passive acoustic study on blue whales). The Commenter asserts it is not clear from the proposed rule, or from the Navy's recent technical report on acoustic “criteria and thresholds,” on which NMFS' approach here is based, exactly how each of the studies that NMFS employed was applied in the analysis, or how the functions were fitted to the data, but the available evidence on behavioral response raises serious concerns that the functions are not conservative for some species. For this reason and others, and given the obvious importance of this analysis for future acoustic impact analyses, the Commenter requests that NMFS make additional technical information available, including from any expert elicitation and peer review, and to re-open public comment on this issue.
Response:
We refer the Commenter to the Criteria and Thresholds for the U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) Technical Report (U.S. Department of the Navy, 2017) for details on how the Navy accounted for the differences in captive and wild animals in the development of the behavioral response risk functions, which NMFS has evaluated and deemed appropriate to incorporate into the analysis in the rule. The appendices to this report detail the specific data points used to generate the behavioral response functions. Data points come from published data that is readily available and cited within the technical report, and NMFS disagrees that it is necessary to re-open public comment on this issue.
The Navy uses the best available science in the analysis, which has been reviewed by external scientists and approved by NMFS. The Navy considered all data available at the time for the development of updated criteria and thresholds, and limiting the data to the small number of field studies would not provide enough data with which to develop the new risk functions. In addition, the Navy accounts for the fact that captive animals may be less sensitive, and the scale at which a moderate-to-severe response was considered to have occurred is different for captive animals than for wild animals, as the Navy understands those responses will be different. The new risk functions were developed in 2016, before several recent papers were published or the data were available. The Navy and NMFS continue to evaluate the information as new science is made available. The criteria have been rigorously vetted within the Navy community, among scientists during expert elicitation, and then reviewed by the public before being applied. It is unreasonable to revise and update the criteria and risk functions every time a new paper is published. NMFS concurs with the Navy's evaluation and conclusion that there is no new information that necessitates changing the acoustic thresholds at this time.
These new papers provide additional information, and the Navy is considering them for updates to the criteria in the future, when the next round of updated criteria will be developed. Regarding consideration of research findings involving a passive acoustic study on blue whale vocalizations and behavior, the Navy considered multiple recent references, including but not limited to: Paniagua-Mendoza, 2017; Lesage, 2017; DeRuiter, 2017; Mate, 2016; Lomac-MacNair, 2016; Friedlaender, 2016; Mate, 2015. Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of this Supplemental EIS/OEIS. To be included in the BRF, data sets needed to relate known or estimable received levels to observations of individual or group behavior. Melcon
et al.
(2012) does not relate observations of individual/group behavior to known or estimable received levels at that individual/group. In Melcon
et al.
(2012), received levels at the HARP buoy averaged over many hours are related to probabilities of D-calls, but the received level at the blue whale individuals/group are unknown.
Comment 8:
A Commenter commented that dipping sonar, like hull-mounted sonar, appears to be a significant predictor of deep-dive rates in beaked whales, with the dive rate falling significantly (
e.g.,
to 35 percent of that individual's control rate) during sonar exposure, and likewise appears associated with habitat abandonment. According to the Commenter, the data sources used to produce the Navy's behavioral response functions (BRF) concern hull-mounted sonar, an R/V-deployed sonar playback, or an in-pool source. The Navy's generic behavioral response function for beaked whales does not incorporate their heightened response to these sources, although such a response would be presumed to shift its risk function “leftward.” Nor do the response functions for other species account for this difference, although unpredictability is known to exacerbate stress response in a diversity of mammalian species and should conservatively be assumed, in this case, to lead to a heightened response in marine mammal species other than beaked whales.
Response:
In consultation with NMFS, the Navy relied upon the best science that was available to develop the behavioral response functions. The current beaked whale BRF acknowledges and incorporates the increased sensitivity observed in beaked whales during both behavioral response studies and during actual Navy training events, as well as the fact that dipping sonar can have greater effects than some other sources with the same source level. Specifically, the distance cut-off for beaked whales is 50 km, larger than any other group. Moreover, although dipping sonar has a significantly lower source level than hull-mounted sonar, it is included in the category of sources with larger distance cut-offs, specifically in acknowledgement of its unpredictability and association with observed effects. This means that “takes” are reflected at lower received levels that would have been excluded because of the distance for other source types.
An article referenced by the Commenter (Associating patterns in movement and diving behavior with sonar use during military training exercises: A case study using satellite tag data from Cuvier's beaked whales at the Southern California Anti-submarine Warfare Range (Falcone
et al.,
2017)) was not available at the time the BRFs were developed. However, NMFS and the Navy have reviewed the article and concur that neither this article nor any
other new information that has been published or otherwise conveyed since the proposed rule was published changes the assessment of impacts or conclusions in the 2020 MITT FSEIS/OEIS or in this rulemaking. Additionally, the Navy's current beaked whale BRF covers the responses observed in this study since the beaked whale risk function is more sensitive than the other risk functions at lower received levels. The researchers involved with the study are still refining their analytical approach and integrating additional statistical parameters for future reporting. Nonetheless, the new information and data presented in the article were thoroughly reviewed by the Navy and will be quantitatively incorporated into future behavioral response functions, as appropriate, when and if other new data that would meaningfully change the functions would necessitate their revision.
Furthermore, ongoing Navy funded beaked whale monitoring at the same site where the dipping sonar tests were conducted has not documented habitat abandonment by beaked whales. Passive acoustic detections of beaked whales have not significantly changed over ten years of monitoring (DiMarzio
et al.,
2018, updated in 2020). From visual surveys in the area since 2006 there have been repeated sightings of: The same individual beaked whales, beaked whale mother-calf pairs, and beaked whale mother-calf pairs with mothers on their second calf (Schorr
et al.,
2018, 2020). Satellite tracking studies of beaked whales documented high site fidelity to this area (Schorr
et al.,
2018, updated in 2020).
Comment 9:
A Commenter recommends that NMFS (1) explain why, if the constants and exponents for onset mortality and onset slight lung injury thresholds for the current phase of incidental take rulemaking for the Navy (Phase III) have been amended to account for lung compression with depth, they result in lower rather than higher absolute thresholds when animals occur at depths greater than 8 m and (2) specify what additional assumptions were made to explain this counterintuitive result.
Response:
The derivation of the explosive injury equations, including any assumptions, is provided in the 2017 technical report titled “Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III).” Specifically, the equations were modified in Phase III to fully incorporate the injury model in Goertner (1982), specifically to include lung compression with depth. NMFS independently reviewed and concurred with this approach.
The impulse mortality/injury equations are depth dependent, with thresholds increasing with depth due to increasing hydrostatic pressure in the model for both the previous 2015-2020 phase of rulemaking (Phase II) and Phase III. The underlying experimental data used in Phase II and Phase III remain the same, and two aspects of the Phase III revisions explain the relationships the Commenter notes:
(1) The numeric coefficients in the equations are computed by inserting the Richmond et al. (1973) experimental data into the model equations. Because the Phase III model equation accounts for lung compression, the plugging of experimental exposure values into a different model results in different coefficients. The numeric coefficients are slightly larger in Phase III versus Phase II, resulting in a slightly greater threshold near the surface.
(2) The rate of increase for the Phase II thresholds with depth is greater than the rate of increase for Phase III thresholds with depth because the Phase III equations take into account the corresponding reduction in lung size with depth (making an animal more vulnerable to injury per the Goertner model), as the Commenter notes.
Ranges to effect are based on these injury thresholds, in addition to geometry of exposure (location of an animal relative to the explosive charge, horizontally and vertically), propagation environment, and the impulse integration duration.
Comment 10:
A Commenter recommends that NMFS use onset mortality, onset slight lung injury, and onset GI tract injury thresholds rather than the 50-percent thresholds to estimate both the numbers of marine mammal takes and the respective ranges to effect. If NMFS does not implement the recommendation, the Commenter further recommends that NMFS (1) specify why it is inconsistently basing its explosive thresholds for Level A harassment on onset of PTS and Level B harassment on onset of TTS and onset of behavioral response, while the explosive thresholds for mortality and Level A harassment are based on the 50-percent criteria for mortality, slight lung injury, and GI tract injury, (2) provide scientific justification supporting that slight lung and GI tract injuries are less severe than PTS and thus the 50-percent rather than onset criteria are more appropriate for estimating Level A harassment for those types of injuries, and (3) justify why the number of estimated mortalities should be predicated on at least 50 percent rather than 1 percent of the animals dying.
Response:
As appropriate, NMFS and the Navy have used a combination of exposure thresholds and consideration of mitigation to inform the take estimates. The Navy used the range to one percent risk of mortality and injury (referred to as “onset” in the 2020 MITT FSEIS/OEIS) to inform the development of mitigation zones for explosives. Ranges to effect based on one percent risk criteria were examined to ensure that explosive mitigation zones would encompass the range to any potential mortality or non-auditory injury, affording actual protection against these effects. In all cases, the mitigation zones for explosives extend beyond the range to one percent risk of non-auditory injury, even for a small animal (representative mass = 5 kg).
Given the implementation and expected effectiveness of this mitigation, the application of the indicated threshold is appropriate for the purposes of estimating take. Using the 1 percent non-auditory injury risk criteria to estimate take would result in an over-estimate of take, and would not afford extra protection to any animal. Specifically, calculating take based on marine mammal density within the area that an animal might be exposed above the 1 percent risk criteria would over-predict effects because many of those exposures will not happen because of the effective mitigation. The Navy, in coordination with NMFS, has determined that the 50 percent incidence of occurrence is a reasonable representation of a potential effect and appropriate for take estimation, given the mitigation requirements at the 1 percent threshold, and the area ensonified above this threshold would capture the appropriate reduced number of likely injuries.
Although the commenter implies that the Navy did not use extensive lung hemorrhage as indicative of mortality, that statement is incorrect. Extensive lung hemorrhage is assumed to result in mortality, and the explosive mortality criteria are based on extensive lung injury data. See the 2017 technical report titled “Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III).”
Comment 11:
A Commenter stated that NMFS, following the Navy, has applied a post-modeling adjustment to its estimate of lethal take that substantially reduces the total number. That adjustment, in the case of serious injury and mortality, purports to account for the effectiveness of visual observers in detecting marine mammals within the blast zone of an underwater
explosion (or within the radius of permanent acoustic injury), but NMFS' borrowed methods here are non-transparent and misconceived. The Navy's DSEIS/OEIS for the MITT Study Area starts with the species-specific g(0) factors applied in professional marine mammal abundance surveys (the probability that an object that is on the line is detected using standard line-transect methods), then multiplies them by simple factors to reflect the relative effectiveness of its Lookouts in routine operating conditions. Yet the Navy's sighting effectiveness is likely to be much poorer than that of experienced biologists dedicated exclusively to marine mammal detection, operating under conditions that maximize sightings. In any case, the public has no meaningful way to further evaluate the agencies' adjustment since the proposed rule does not provide the scores used to generate the effectiveness factor or the agencies' pre-adjustment take numbers, nor does the Navy in the ancillary report NMFS references. The Commenter suggests that “[s]ince the Navy has yet to determine the effectiveness of its mitigation measures, it is premature to include any related assumptions to reduce the numbers of marine mammal takes.” Another Commenter recommends that NMFS (1) specify the total numbers of model estimated Level A harassment (PTS) and mortality takes rather than reduce the estimated numbers of takes based on the Navy's post-model analyses and (2) include the model-estimated Level A harassment and mortality takes in its negligible impact determination analyses.
Response:
The consideration of marine mammal avoidance and mitigation effectiveness is integral to NMFS' and the Navy's overall analysis of impacts from sonar and explosive sources. NMFS has independently evaluated the method and agrees that it is appropriately applied to augment the model in the prediction and authorization of injury and mortality as described in the rule. Details of this analysis are provided in the Navy's 2018 technical report titled “Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing.” Additional information on the mitigation analysis also was included in the proposed rule and NMFS disagrees with the Commenter's suggestion that there was not enough information by which to evaluate the Navy's post-modeling calculations. Also, it should be noted that even before consideration of mitigation effectiveness, there were no modeled mortalities to any marine mammals.
Sound levels diminish quickly below levels that could cause PTS. Specifically, behavioral response literature, including the recent 3S and SOCAL BRS studies, indicate that multiple species from different cetacean suborders do in fact avoid approaching sound sources by a few hundred meters or more, which would reduce received sound levels for individual marine mammals to levels below those that could cause PTS (see Appendix B of the “Criteria and Thresholds for U.S. Navy Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles Technical Report” (U.S. Department of the Navy, 2017) and Southall
et al.
(2019a)). The ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases. For blue whales and other LF cetaceans, the range to PTS is 65 m for MF1 30 sec duration exposure, which is well within the mitigation zones for hull-mounted MFAS. Therefore, the anticipated avoidance to the distances discussed would greatly reduce the likelihood of impacts to hearing such as TTS and PTS. As discussed in the Navy's report, animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way. Accordingly, NMFS and the Navy's analysis appropriately applies a quantitative adjustment to the exposure results calculated by the model (which does not consider avoidance or mitigation).
As discussed in the Navy's report, the Navy's acoustic effects model does not consider procedural mitigations (
i.e.,
power-down or shut-down of sonars, or pausing explosive activities when animals are detected in specific zones adjacent to the source), which necessitates consideration of these factors in the Navy's overall acoustic analysis. Credit taken for mitigation effectiveness is extremely conservative. For example, if Lookouts can see the whole area, they get credit for it in the calculation; if they can see more than half the area, they get half credit; if they can see less than half the area, they get no credit. Not considering animal avoidance and mitigation effectiveness would lead to a great overestimate of injurious impacts. NMFS concurs with the analytical approach used,
i.e.,
we believe the estimated take by Level A harassment numbers represent the maximum number of these takes that are likely to occur and it would not be appropriate to authorize a higher number or consider a higher number in the negligible impact analysis.
The Navy assumes that Lookouts will not be 100 percent effective at detecting all individual marine mammals within the mitigation zones for each activity. This is due to the inherent limitations of observing marine species and because the likelihood of sighting individual animals is largely dependent on observation conditions (
e.g.,
time of day, sea state, mitigation zone size, observation platform) and animal behavior (
e.g.,
the amount of time an animal spends at the surface of the water). The Navy quantitatively assessed the effectiveness of its mitigation measures on a per-scenario basis for four factors: (1) Species sightability, (2) a Lookout's ability to observe the range to permanent threshold shift (for sonar and other transducers) and range to mortality (for explosives), (3) the portion of time when mitigation could potentially be conducted during periods of reduced daytime visibility (to include inclement weather and high sea-state) and the portion of time when mitigation could potentially be conducted at night, and (4) the ability for sound sources to be positively controlled (
e.g.,
powered down). The Navy's report clearly describes how these factors were considered, and it is not necessary to view the many tables of numbers generated in the assessment to evaluate the method.
The g(0) values used by the Navy for their mitigation effectiveness adjustments take into account the differences in sightability with sea state, and utilize averaged g(0) values for sea states of 1-4 and weighted as suggested by Barlow (2015). Using g(0) values is an appropriate and conservative approach (
i.e.,
underestimates the protection afforded by the Navy's mitigation measures) for the reasons detailed in the technical report. For example, during line-transect surveys, there are typically two primary observers searching for animals. Each primary observer looks for marine species in the forward 90-degree quadrant on their side of the survey platform and scans the water from the vessel out to the limit of the available optics (
i.e.,
the horizon). Because Navy Lookouts focus their observations on established mitigation zones, their area of observation is typically much smaller than that observed during line-transect surveys. The mitigation zone size and distance to the observation platform varies by Navy activity. For example, during hull-mounted mid-frequency active sonar activities, the mitigation zone extends 1,000 yd from the ship
hull. During the conduct of training and testing activities, there is typically at least one, if not numerous, support personnel involved in the activity (
e.g.,
range support personnel aboard a torpedo retrieval boat or support aircraft). In addition to the Lookout posted for the purpose of mitigation, these additional personnel observe for and disseminate marine species sighting information amongst the units participating in the activity whenever possible as they conduct their primary mission responsibilities. However, as a conservative approach to assigning mitigation effectiveness factors, the Navy elected to account only for the minimum number of required Lookouts used for each activity; therefore, the mitigation effectiveness factors may underestimate the likelihood that some marine mammals may be detected during activities that are supported by additional personnel who may also be observing the mitigation zone.
Although NAEMO predicted PTS, no mortality or non-auditory injury were predicted by NAEMO. Of these two non-auditory effects (mortality and non-auditory injury), only mortality would have been subject to mitigation consideration in the quantitative analysis, if there had been any. Also, as discussed in
Comment 43,
the Navy will be providing NMFS with a report summarizing the status of and/or providing its final assessment on the Navy's Lookout Effectiveness Study following the end of CY 2021.
Comment 12:
One Commenter asserted that NMFS and the Navy make certain post-modeling adjustments to their estimates of non-lethal injury, on flawed assumptions about animal avoidance and mitigation effectiveness. A Commenter stated in regards to the method by which the Navy's post-model calculation considers avoidance specifically
(i.e.,
assuming animals present beyond the range of PTS for the first few pings will be able to avoid it and incur only TTS, which results in a 95 percent reduction in the number of estimated PTS takes predicted by the model), given that sound sources are moving, it may not be until later in an exercise that the animal is close enough to experience PTS, and it is those few close pings that contribute to the potential to experience PTS. Marine mammals may remain in important habitat, and the most vulnerable individuals may linger in an area, notwithstanding the risk of harm; marine mammals cannot necessarily predict where an exercise will travel. In addition, Navy vessels may move faster than the ability of the animals to evacuate the area. The Commenter expressed concern that this method underestimates the number of PTS takes and that NMFS should not create an under-supported, nonconservative adjustment for avoidance. The Commenter further suggested that the Navy could query the dosimeters on the animats in its model to test its assumption.
Response:
The consideration of marine mammals avoiding the area immediately around the sound source is provided in the Navy's 2018 technical report titled “
Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles.”
As the Commenter correctly articulates: “For avoidance, the Navy assumed that animals present beyond the range to onset PTS for the first three to four pings are assumed to avoid any additional exposures at levels that could cause PTS. That equated to approximately 5 percent of the total pings or 5 percent of the overall time active; therefore, 95 percent of marine mammals predicted to experience PTS due to sonar and other transducers were instead assumed to experience TTS.”
In regard to the comment about vessels moving faster than animals' ability to get out of the way, as discussed in the Navy's 2018 technical report titled “
Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles,”
animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way, necessitating the additional step of considering animal avoidance of close-in PTS zones. NMFS independently reviewed these assumptions and this approach and concurs that they are fully supported by the best available science. Based on a growing body of behavioral response research, animals do in fact avoid the immediate area around sound sources to a distance of a few hundred meters or more depending upon the species. Avoidance to this distance greatly reduces the likelihood of impacts to hearing such as TTS and PTS, respectively. Specifically, the ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases. The Commenter's point about speed is not applicable to the initially distant animals that are discounted by this method, most of which would be able to avoid the source as there is more time (because they are farther from the source) to do so. Further, the Commenter ignores the corollary to their point, which is that given the speed the Navy vessels operating sonar are typically traveling relative to the speed and direction of marine mammals, the likelihood of individuals remaining in close enough proximity to the source for a duration that would result in TTS or PTS is lessened.
Querying the dosimeters of the animats would not produce useful information since, as discussed previously, the animats do not move in the horizontal and are not programmed to “react” to sound or any other stimulus.
Humpback Whales
Comment 13:
Commenters assert that the proposed reporting requirement for MF1 MFAS (with the lack of any restriction on actual sonar use) in the Chalan Kanoa Reef and Marpi Reef Geographic Mitigation Areas would not protect humpback whales, and particularly calves during this sensitive life stage. Further, the Commenters note that because these areas have not been a high‐use area for the Navy and ASW training events and are “considered generally unsuitable for training needs,” (85 FR 48388), there is no justification for failing to prohibit sonar use in this sensitive humpback whale habitat off Saipan. One Commenter recommended that NMFS prohibit use of MF1 sonar in the Marpi Reef and Chalan Kanoa Reef Geographic Mitigation Areas during the months that humpbacks are present in the Marianas while another suggested a year-round prohibition.
Response:
Following extensive discussions with the Navy during which more specific granular information about the Navy's likely activity was provided and the practicability of additional restrictions were considered, new information about humpback whale occurrence in the mitigation areas emerged, and new analyses were conducted (see the
Estimated Take of Marine Mammals
section), NMFS established a 20-hr annual cap from December 1-April 30 on the use of hull-mounted MF1 MFAS for these two Geographic Mitigation Areas (20 hrs total for both areas combined) to minimize sonar exposure and reduce the amount and/or severity of take by Level B harassment (behavioral disturbance and/or TTS) of humpback whales in these important reproductive areas. It is important to note that in the Navy's rulemaking/LOA application and NMFS' associated analysis for the proposed rule, while high amounts of sonar training may not have been expected, the amount of sonar use in these areas had not been limited.
Our evaluation of potential mitigation measures includes consideration of both
(1) the manner in which, and the degree to which, implementation of the potential measure(s) is expected to reduce adverse impacts to marine mammal species or stocks and their habitat and (2) the practicability of the measures for applicant implementation, which in this case includes the impact on the Navy's military readiness activities. While we did consider completely restricting MF1 MFAS in the two Geographic Mitigation Areas, we also considered the Navy's broader need for flexibility as well as the specific need not to restrict these shallow-water training areas entirely in the MITT Study Area given the proximity to forward deployed operations and the higher likelihood of a need to have the option to conduct training quickly to respond to emergent national security threats. The Navy expects current and future use of the two Geographic Mitigation Areas to remain low, but the 20-hr cap will allow the Navy flexibility to engage in a small amount of necessary training, most likely such as a Small Coordinated ASW Exercise or TRACKEX event(s), which could occur up to five days, but no more than four hours per day (or similar configuration totalling no more than 20 hrs). Areas of shallow depths are limited in the Mariana Archipelago, and NMFS determined (with the Navy's input) that it would be impracticable to completely limit the use of sonar at the Chalan Kanoa Reef and Marpi Reef due to the requirement to have access to such bathymetry for training purposes in order to support mission requirements as established by operational Commanders. The reduction in potential exposure of humpback whales to sonar in these areas and at this time (
i.e.,
the short overall and daily exposure) would reduce the likelihood of impacts that could affect reproduction or survival, by minimizing impacts on calves during this sensitive life stage, avoiding the additional energetic costs to mothers of avoiding the area and minimizing the chances that important behaviors (
e.g.,
cow-calf communication, breeding behaviors) are interrupted to the point that survivorship or reproduction are impacted. Therefore, we have determined that the 20-hr cap on MF1 MFAS sonar in the two Geographic Mitigation Areas will meaningfully reduce impacts on the affected humpback whales and, further, be practicable for Navy implementation. As an additional measure, the Navy will also now report all active sonar use (all bins, by bin) in these areas between December 1 and April 30 to NMFS in their annual reports. This will allow NMFS to evaluate the sonar use in the two Geographic Mitigation Areas over the seven-year period and to determine if further mitigation is warranted.
Comment 14:
A Commenter recommended a prohibition on mid-frequency air deployed dipping sonar, year-round in the Geographic Mitigation Areas. The Commenter also commented that dipping sonar has been shown to have disproportionate impacts on beaked whales and may impact other species such as humpback whales in a similar manner, due to the unpredictability of the signal.
Response:
Regarding the applicability of the data the Commenter cites to humpback whale responses, the research was focused exclusively on beaked whales and, further, in regard to the data cited, certain limitations are still under investigation such as the proximity of the source and other factors. Behavioral responses of beaked whales from dipping and other sonars cannot be universally applied to other marine mammal species, especially since beaked whales are known to be more sensitive to lower level sounds, which is reflected in our analysis through a lower behavioral harassment threshold. For example, Navy-funded behavioral response studies of blue whales to simulated surface ship sonar have demonstrated there are distinct individual variations as well as strong behavioral state considerations that influence any response or lack of response. The majority of take by Level B harassment results from MF1 sonar, which is practicable to limit in the Chalan Kanoa Reef and Marpi Reef Geographic Mitigation Areas. Sonar activities in this area have been limited historically, there is insufficient evidence to suggest that MF4 sonar would have disproportionately adverse effects, and further limitation of MF4 dipping sonar use in these areas would not be expected to meaningfully reduce impacts to humpback whales.
With regards to beaked whales, water depths in the Chalan Kanoa Reef and Marpi Reef Geographic Mitigation Areas are not suitable habitats for beaked whales. There is no evidence to suggest that prohibiting the use of mid-frequency dipping sonar in the Geographic Mitigation Areas would have any benefit to beaked whales.
Comment 15:
A Commenter recommended prohibiting use of low-frequency active sonar from December through April in the Marpi Reef and Chalan Kanoa Reef Geographic Mitigation Areas, because they assert that baleen whales are vulnerable to the impacts of low-frequency active sonar, particularly in calving areas where low-amplitude communication calls between mothers and calves can be easily masked.
Response:
Low-frequency sonar use in this rule has been significantly scaled down from previous authorizations. The Navy is only seeking authorization for 11 hrs or less per year of low-frequency sonar use in the MITT Study Area, with most of these systems used further offshore. Furthermore, the most used source at approximately 10 hrs (LF5) has source levels less than 180 dB and one hour of LF4 with source levels greater than 180 dB and less than or equal to 200 dB, with the associated harassment zones significantly smaller than for MF1. Based on historical sonar use in the MITT Study Area, it is highly unlikely that the few planned low-frequency sonar hours would occur in the Geographic Mitigation Areas from December through April. Given that, and the smaller impact zones, a prohibition would have very limited or no potential benefit to humpback whales and other baleen whales and would unnecessarily impose a restriction on training and testing in the MITT Study Area.
Comment 16:
A Commenter recommended extending the Marpi Reef Geographic Mitigation Area boundaries to include a buffer that encompasses the humpback whale sightings data beyond the 400-m depth contour and the southernmost point of the proposed Marpi Reef Geographic Mitigation Area.
Response:
NMFS extended the boundary out to the 400-m isobath for both Marpi Reef and Chalan Kanoa Reef Geographic Mitigation Areas prior to the publication of the proposed rule. NMFS and the Navy considered using bathymetry to define the Marpi Reef Geographic Mitigation Area when initially evaluating potential mitigation areas, but instead relied on confirmed sightings of humpback whales to define the area. After reviewing the detailed bathymetry of the reef coupled with marine mammal sightings, NMFS and the Navy reevaluated how the Marpi Reef Geographic Mitigation Area was bounded and redefined the area based on the extent of the 400-m isobath. Given most sightings of humpback whales were in waters less than 200 m in depth, this provides an additional buffer between most sighting locations and the boundary for the area. Seafloor areas extending beyond the reef are not necessarily areas of potential biological importance (
i.e.,
whales may have been transiting to or from the reef when sighted). Scientists from NMFS' Pacific Islands Fisheries Science Center, who have conducted numerous humpback
whale surveys in Hawaii and the Mariana Islands, have observed that the majority of humpback whale breeding activity (mother-calf pairs, competitive behavior) happens in water depths of 200 m or less, with more mother-calf pairs in water depths 50 m or less (Hill
et al.,
2020). In addition, during a review of the Marpi Reef sightings and bathymetry, the Navy found that the mitigation graphics in Appendix I (Geographic Mitigation Assessment) of the 2020 MITT FSEIS/OEIS had errors where bathymetric lines plotted were incorrectly shifted. This issue was fixed using a more accurate small-scale bathymetric dataset. Revised figures for the 2020 MITT FSEIS/OEIS show that all humpback whale sightings near Marpi Reef where suspected reproductive behaviors were observed (mother-calf pairs, competitive behavior) were shallower than the 200-m isobath.
Comment 17:
A Commenter recommends implementing vessel speed restrictions from December through April in the Marpi Reef and Chalan Kanoa Reef Geographic Mitigation Areas as they argue that ship strike and vessel noise pose a serious risk to humpback whales, particularly in calving and breeding areas. They say it is important that NMFS prescribe vessel speed limits in this important breeding habitat and that mandatory speed limits, such as those that NMFS has put in place to protect North Atlantic right whales, have proven effective. NMFS has no basis on which to determine that its “notification message” measure—which would depend on non-specialist, non-dedicated Navy observers operating effectively in unfavorable sea states—would be as effective, or effective at all. The Commenter states there is no reason why NMFS cannot reasonably accommodate national security needs to create exceptions to the rule if needed.
Response:
To avoid physical disturbance and strike from vessel movements, the Navy maneuvers to maintain a 500 yd mitigation zone from whales and other marine mammals (except bow-riding dolphins). As further described in Section 5.3.4.1 (Vessel Movement) of the 2020 MITT FSEIS/OEIS implementing mitigation to limit vessel speeds in the MITT Study Area would be incompatible with the Navy's criteria for safety, sustainability, and mission requirements. For example, Navy vessel operators need to train to proficiently operate vessels as they would during military missions and combat operations, including being able to react to changing tactical situations and evaluate system capabilities. Navy studies from other range complexes demonstrated that median speeds near coasts are already low, varying from 5 to 12 knots. Furthermore, given that there have been no vessel strikes involving humpback whales or other marine mammals while Navy vessels conducted training and testing activities in the MITT Study Area, implementing vessel speed restrictions in the Geographic Mitigation Areas or other locations in the Study Area would not be an effective mitigation measure because it would not result in discernible avoidance or reduction of impacts. Given the lack of meaningful reduction in impacts combined with the impracticability of ship speed restrictions, NMFS has found that this measure is not warranted and it is not required in this rule.
Serious Injury and Mortality, Beaked Whales
Comment 18:
Commenters stated that NMFS underestimated serious injury and mortality for beaked whales around the Mariana Islands, ignored the best available scientific information, and failed to make any meaningful assessment and negligible impact determination of the likelihood that Navy training and testing activities triggered strandings in the MITT Study Area. A Commenter stated that NMFS has failed to demonstrate a rational basis for its assumption that “[n]o mortality or Level A harassment [of beaked whales] is expected” from MITT activities, rendering NMFS's preliminary determination of negligible impact arbitrary and capricious. Another Commenter noted that in the Guam press, at least six beaked whale stranding events, each involving as many as three animals, have been reported in the archipelago since 2006, as compared with only a single stranding in the previous 35 years. That number of recent stranding events was subsequently corrected to eight, in a paper that appeared earlier this year in a major, peer-reviewed journal. The Simonis
et al.
(2020) paper, whose co-authors include several NMFS biologists, correlated four of these events with Navy operations, a correlation that it describes as “highly significant.” The Commenter argued that the best available science shows that serious injuries and mortalities are likely to far exceed the number of reported strandings. Numerous studies along multiple lines of evidence, including post-stranding pathology, laboratory study of organ tissue, and theoretical work on dive physiology, in addition to expert reviews, indicate that behaviorally-mediated injury and mortality is occurring through maladaptive alteration of the dive pattern in response to Navy sonar exposure—impacts that occur at sea, independent of a whale's stranding. The Commenter argues that in light of the available scientific evidence, this position is both arbitrary and irresponsible. They state that NMFS' method in the proposed rule is to cast doubt on an undefined subset of previous stranding events on the grounds that the precise mechanism of harm could not be established, even while describing in detail the abundance of pathological and forensic evidence.
In a related comment, another Commenter asserted that although NMFS does not expect injury or mortality of any of beaked whales to occur as a result of the Navy's active sonar training exercises, NMFS's justification for authorizing beaked whale mortalities under Phase I and the previous Phase II regulations is still valid. The Commenter argues that NMFS cannot ignore that there remains the potential for the operation of MFAS to contribute to the mortality of beaked whales. Given that the potential for beaked whale mortalities cannot be obviated, the Commenter recommends that NMFS authorize at least 10 mortality takes of beaked whales associated with MFA sonar use in the MITT Study Area in the final rule.
Response:
In the final rule, NMFS has included additional information and analysis and expanded the explanation of why the best available science does not indicate that the Navy's activities are likely to result in mortality of beaked whales through stranding. Please see the
Stranding
subsection of the
Potential Effects of Specified Activities on Marine Mammals and Their Habitat
section, which addresses the issues raised by the Commenters; comments not addressed in that section are addressed below. To specifically correct an inaccuracy in the Comment, it should be noted, that of the eight events the Commenter refers to, only three had Navy sonar use before. Four events cited in the paper was an error the authors acknowledged.
In regard to the authorization of mortality in MMPA regulations for Phase I and II of MITT training and testing activities, the Commenter is in error. Mortality was authorized in the Phase I MITT final rule, in an abundance of caution given the events, worldwide, in which there was a causal link between naval sonar and strandings, and noting that there could be a stranding that co-occurred with Navy sonar that was not caused by it. However, the rule explicitly stated that
“Neither NMFS nor the Navy anticipates that marine mammal strandings or mortality will result from the use of mid- or high-frequency sonar during Navy exercises within the MIRC Study Area.” However, no mortality was authorized in the Phase II final rule for the MITT Study Area. The Navy initially requested mortality takes of beaked whales, however, after further discussion of the lack of incidents in which strandings were causally associated with sonar in the Marianas, or a perceived reasonable likelihood that they would be at the time, NMFS and the Navy determined that authorization of mortality was not appropriate. NMFS does not argue that there is no possibility for mortality to occur as a result of Navy activities, rather, we reason that consideration of all applicable information (the best available science) does not indicate that such mortality is reasonably likely to result from the Navy's activities within the seven-year span of the rule.
Comment 19:
A Commenter stated that in addition to documenting the substantial risk of injury and mortality to beaked whales from MITT activities, Simonis
et al.
(2020) confirmed the existence of biologically important areas for beaked whales near Saipan and Tinian. The study found that at least three species of beaked whales—Cuvier's, Blainville's, and a third unidentified species that may be the ginkgo‐toothed beaked whale—occur in the Mariana Archipelago throughout the year, similar to other island‐associated populations around the world. The Commenter argues that before finalizing its MMPA take regulations and issuing an LOA, NMFS must fully evaluate this new scientific information, which supports the establishment of a geographic mitigation area in the waters around Saipan and Tinian to protect vulnerable beaked whales from Navy sonar.
Response:
NMFS has evaluated the new scientific information from Simonis
et al.
(2020) as well as years of field surveys conducted under interagency agreements between the Navy and NMFS Pacific Islands Fisheries Science Center and Navy-funded beaked whale monitoring, and there remains a lack of scientific information available on beaked whale distribution in the Marianas Islands. Simonis
et al.
(2020) confirm that the acoustic record from their HARPs indicates that the habitats near the recording locations are used by Blainville's, Cuvier's and an unidentified beaked whale, however, they only suggest that the locations “may be considered as potentially important beaked whale habitat,” given that beaked whales were present a large portion of the time at each recording site. Specifically, they note that the presence of beaked whale signals in a recording can be indicative of relative occurrence and seasonal fluctuations, however, given there are only two recorders, the relative occurrence may only be compared between the two locations, and the authors do not compare the recordings to any other locations, making it impossible to draw conclusions regarding how any inferred occurrence rates might compare to other parts of the MITT Study Area or the species' range. The information presented in Simonis
et al.
(2020), while informative, does not provide sufficient information to warrant the addition of geographic mitigation measures beyond the procedural mitigation measures put in place through this final rule to reduce the number and severity of takes for all marine mammals.
Without sufficient scientific data on beaked whale habitat use, bathymetry, and seasonality, NMFS is unable to develop mitigation measures that will meaningfully further reduce impacts to beaked whales and not be impracticable for the Navy. That said, NMFS and the Navy are committed to further actions (see the
Changes from the Proposed Rule to the Final Rule
section) to expand the science and inform future management actions related to beaked whales in the MITT Study Area. For example, the Navy will co-fund the Pacific Marine Assessment Program for Protected Species (PACMAPPS) survey in spring-summer 2021 to help document beaked whale occurrence, abundance, and distribution in the Mariana Islands. This effort will include deployments of a towed array as well as floating passive acoustic buoys. The Navy will monitor future beaked whale occurrence within select portions of the MITT Study Area starting in 2022. Additionally, the Navy will include Cuvier's beaked whales as a priority species for analysis under a 2020-2023 Navy-funded research program entitled Marine Species Monitoring for Potential Consequences of Disturbance (MSM4PCOD). Finally, the Navy will fund and co-organize with NMFS an expert panel to provide recommendations on scientific data gaps and uncertainties for further protective measure consideration to minimize the impact of Navy training and testing activities on beaked whales in the Mariana Islands.
Comment 20:
One Commenter made several recommendations related to NMFS' assessment and mitigation of beaked whale impacts. The Commenter recommended that given beaked whales infrequent exposure to active sonar in the MITT Study Area, more conservative behavioral response curves be used to predict behavioral disturbance. The Commenter also challenged NMFS' assertion that suitable alternative foraging habitat is available for beaked whales in the MITT Study Area. Noting the scarcity of beaked whale data, the Commenter recommended that acoustic monitoring be implemented as the preferred method for estimating density of beaked whales, instead of using Hawaii data and, further, recommended more broadly that acoustic monitoring of beaked whales be conducted to better understand the impacts of Navy activities on beaked whales. The Commenter recommended that the Navy be more transparent in their monitoring in sharing data indicating the timing of Navy activities in relation to strandings. The Commenter noted that additional personnel and support for local stranding response and records is needed in order to better investigate causes of strandings that coincide with Navy activities in the MITT Study Area. Last, the Commenter notes that in order to detect any trend in the population, there is a strong need to conduct consistent surveys, with adequate methods for the species under consideration, over multiple years.
Response:
Regarding the recommendation to modify the behavioral harassment thresholds (specifically, lower the received levels at which they would be considered taken) based on the infrequent exposures of beaked whales to sonar in the Marianas, we first note that although the amount of activities in the MITT Study Area is below the amount in the AFTT or HSTT study areas, active sonar has been in regular use in the MITT Study Area since the 1960s, and it is unlikely that marine mammals in the area are naive to sonar exposure. Further, while NMFS acknowledges the importance of context and considers it in evaluating behavioral responses, there is not sufficient data upon which to base a quantitative modification of the behavioral harassment thresholds. Further, the behavioral thresholds for beaked whales are already lower than for other taxa to address their sensitivity and, as with other taxa, take the form of a dose response curve, allowing for variation in individual responses given different contexts.
Regarding the comment that NMFS claims that suitable alternative habitat options exist if beaked whales are disturbed during feeding is not credible, we first direct the Commenter to the discussion of the impacts of noise
exposure during feeding behaviors described in the
Odontocete
subsection of the
Analysis and Negligible Impact Determination
section, which discusses the energetic impacts that interruption of feeding bouts can have on feeding odontocetes if interruptions occur over repeated sequential days. However, in the context of the MITT Study Area, as predicted and discussed, the magnitude and severity of takes is such that disturbance of low-moderate levels is expected to occur on no more than a few non-sequential days for any individual beaked whales, which would not result in the sort of energetic concerns that the Commenter is raising. Further, the Commenter repeatedly references concerns for small resident populations of beaked whales with high site fidelity, but there are no data to confirm the population structure of beaked whales in this area and, again, the magnitude and severity is low such that, regardless, adverse energetic impacts would be unlikely to result from Navy activities.
Regarding the recommendation that acoustic monitoring be implemented in order to provide better density information for beaked whales, and to better understand behavioral responses, as noted in the
Changes from the Proposed Rule
section, the Navy will be co-funding the Pacific Marine Assessment Program for Protected Species (PACMAPPS) survey in spring-summer 2021 to help document beaked whale occurrence, abundance, and distribution in the Mariana Islands. This effort will include deployments of a towed acoustic array as well as floating passive acoustic buoys. The Navy has further committed to monitoring future beaked whale occurrence within select portions of the MITT Study Area starting in 2022 (so as to not duplicate PACMAPPS efforts).
Regarding the recommendation that the Navy be more transparent in their monitoring and sharing data indicating the timing of Navy activities in relation to strandings, there is certain information that the Navy is unable to share freely because it is classified. Specific classified information is shared in the Navy's classified monitoring reports, and the Navy has always cooperated to provide additional detail in an unclassified format when needed. Further, though, the Navy has specifically targeted, for monitoring pursuant to this rule, increased analysis for any future beaked whale stranding in the Mariana Islands to include detailed Navy review of available records of sonar use.
Regarding the comment that additional personnel and support for local stranding response and records is needed in order to better investigate causes of strandings that coincide with Navy activities in the MITT Study Area, as discussed in the rule the Navy has committed to continuing to fund additional stranding response/necropsy analyses for the Pacific Islands region. Further, the Navy is submitting a proposal through the annual Federally Funded Research and Development Center (FFRDC) call to fund the Center for Naval Analysis (CNA) to develop a framework to improve the analysis of single and mass stranding events, including the development of more advanced statistical methods to better characterize the uncertainty associated with data parameters.
Last, the Commenter notes that in order to detect any trend in the population, there is a strong need to conduct consistent surveys, with adequate methods for the species under consideration, over multiple years. NMFS and the Navy do not disagree with this recommendation and, as noted, the Navy and NMFS are co-funding the PACMAPPS survey and the Navy has committed to additional beaked whale surveys. However, the ability to conduct consistent surveys is dependent upon the availability of resources at both NMFS and the Navy, and surveys may not always be conducted with the ideal regularity.
Comment 21:
A Commenter recommends that the Navy conduct more visual monitoring efforts, at sea and along coastlines, for stranded cetaceans before, during, and after naval exercises.
Response:
It is not practicable for the Navy to conduct additional visual monitoring at sea and along the coastlines for stranded cetaceans before, during, and after training and testing activities beyond what will occur through the procedural mitigation requirements under this rule. Pursuant to the mitigation, the Navy will be required to conduct monitoring for marine mammals before, during, and after in-water explosive exercises as described in the
Mitigation Measures
section of this rule. During operations of hull-mounted mid-frequency sonar and low frequency sonar above 200 dB, monitoring will be conducted in support of mitigation requirements, and during all operations of any sort the Navy will be required to report if any injured or dead marine mammals are observed and follow established incident reporting procedures. In addition, the Navy has been providing funding to augment stranding response and necropsy examinations in Hawaii and the Mariana Islands since 2018. Additional funding to continue this support has been programmed and is pending issuance in FY20.
Comment 22:
A Commenter recommends that NMFS consider the full range of options in determining the mitigation measures needed to meet its responsibility under both the “negligible impact” and “least practicable adverse impact” provisions of the MMPA for beaked whales. Given the expertise needed to produce an optimal mitigation plan, the Commenter strongly advises NMFS to assemble a group of subject-matter experts, including experts on beaked whale distribution, monitoring, and conservation from the Southwest Fisheries Science Center, researchers from the Pacific Islands Fisheries Science Center who have led the work on beaked whales in the archipelago, and outside experts on the conservation biology of beaked whales.
Response:
The procedural mitigation measures required by the final rule provide protection for all species of marine mammals by reducing the probability and severity of impacts from active sonar and explosives. As noted, there is limited data available addressing the distribution of marine mammals in the Marianas, and there is no information supporting the existence of any known biologically important areas that would warrant the development of a geographic mitigation area for beaked whales. NMFS had thorough discussions with the Navy about the possibility of crafting a mitigation measure to minimize any potential risk that Navy activities could contribute in any way to the potential stranding of beaked whales. These discussions included consideration of all public comments that recommended beaked whale mitigation measures. However, despite years of field surveys conducted under interagency agreements between the Navy and NMFS' PIFSC along with Navy funded beaked whale monitoring, there remains a lack of scientific information available on beaked whale distribution and other essential species information in the Mariana Islands. Without sufficient scientific data on beaked whale habitat use, bathymetry, and seasonality, and from that a better understanding of the circumstances that could affect the likelihood of a stranding in the MITT Study Area, NMFS is unable to develop mitigation measures that would meaningfully reduce the likelihood of stranding and/or will not result in unreasonable operational/practicability concerns.
Consequently, NMFS recommended to the Navy that the two agencies convene a panel of experts, both from
the region, as well as beaked whale behavioral response experts from other geographic areas, and Navy experts on biology, operations, and mitigation to review the status of the science, identify data gaps, and identify information applicable for consideration for future mitigation through the Adaptive Management process. The Navy has agreed to fund and co-organize this effort. Additional measures that the Navy has agreed to conduct to increase understanding and decrease uncertainty around beaked whales in the MITT Study Area are discussed in the
Monitoring
section.
Comment 23:
A Commenter recommends that the impact assessment consider whether beaked whales would be startled by explosions or active sonar causing them to rush from great depths to the surface at dangerous speed causing injury from gas expansion in their blood and whether repeated impacts causing TTS could lead to PTS.
Response:
The proposed rule addressed the impacts the commenter raises in the
Potential Effects of Specified activities on Marine Mammals and Their Habitat
section (
Acoustically Mediated Bubble Growth and other Pressure-related Injury).
Further, NMFS has expanded the discussion and rationale describing why the Navy's activities are not expected to result in the mortality of beaked whales in the
Stranding
section of this final rule.
As described in the proposed rule, very prolonged or repeated exposure to sound strong enough to elicit TTS, or shorter-term exposure to sound levels well above the TTS threshold, can cause PTS, however, circumstances that would be expected to lead to this are not present for Navy activities in the MITT Study Area. For this rulemaking, the Navy's modeling has considered the proximity of marine mammals to Navy activities and the likelihood of exposure to levels above which TTS or PTS might be incurred, throughout a full day (
i.e.,
considering potential repeated exposures within a day), and very few PTS takes are expected (see the
Estimated Take of Marine Mammals
section). Further, as discussed in the
Analysis and Negligible Impact Determination
section, there is no information suggesting that any marine mammals will be exposed to levels resulting in TTS across more than a few non-sequential days, much less at a level or duration that is expected to accrue to PTS across those days.
Also of note, ongoing research on beaked whale response to sonar does not indicate a panic response and rush to the surface. Instead, beaked whales move away from the source underwater and increase the slope of their ascent glide to bring them further from the source (Falcone et al. 2017).
Comment 24:
A Commenter stated that similar to beaked whales, NMFS has failed to analyze seriously whether melon‐headed whales and other marine mammal species known to be vulnerable to harm from Navy sonar and explosives are likely to suffer injury and/or death from MITT activities.
Response:
There have not been significant instances of stranding of melon-headed whales or other blackfish species in the Mariana Islands. Effects analyses concluding that strandings of these species are unlikely to result from the Navy's activities are contained in the 2020 MITT FSEIS/OEIS. In review of NMFS' and Guam Department of Agriculture's Division of Aquatic and Wildlife Resources stranding data from 1962 through February 2019, only two instances of melon-headed whale strandings were reported (1980 and 2015). Stranding data for other species over the same time period include: false killer whale 3 (2000, 2003, 2007), dwarf sperm whale 4 (1970, 1974, 1993, 2002), pygmy killer whale 1 (1974), pygmy sperm whale 3 (1989 (2), 1997), sperm whale 6 (1962, 1993 (2), 2011, 2012, 2013), and short-finned pilot whale 1 (1980). Given the low numbers of strandings of these species in the Marianas and the absence of any evidence of association with active sonar operation, the likelihood that Navy activities would result in serious injury or mortality of these species is considered discountable.
Comment 25:
A Commenter stated that NMFS assumes, counter to the available evidence, that beaked whales around the Mariana Archipelago have no population structure and are part of large, cosmopolitan populations. While limited information on population structure is available, the best available science shows differences in the echolocation signal frequency of Blainville's beaked whales between the Northern Marianas Islands and other locations in the Pacific, Western Atlantic, and Gulf of Mexico, indicative of a population specific to the Northern Marianas Islands. This finding is consistent with studies in other parts of the world, which have demonstrated remarkable site-fidelity in beaked whale populations. Range-limited populations have been found on the shelf break approximately 50 km east of Cape Hatteras, as well as off Canada, in the Mediterranean, off Southern California, in the Bahamas, and around the Hawaiian Islands.
Response:
There is no satellite tag or photographic identification data supporting the assertion that the populations around the Marianas are resident populations, much less identifying what the size or shape of those resident populations might be within the Mariana Islands (
i.e.,
abundance and range size). The Commenter points to data differentiating vocalizations of Blainville's beaked whales in the Mariana Islands versus other parts of the Pacific, and to the presence of known resident populations of beaked whales in Hawaii and other islands of the world. These points support the potential for resident populations to exist in the Marianas, but do not provide any information that would support analyzing impacts in a manner differently than was done by the Navy and NMFS. Specifically, for example, even if the beaked whales within the Marianas comprise a separate population from those elsewhere in the Pacific, it would not suggest that beaked whales should be analyzed differently than they were within the MITT Study Area.
While NMFS cannot explicitly define the beaked whale population structure at this time, the magnitude and severity of the estimated take and the negligible impact analyses remain valid and applicable based on the best available science regardless of whether the beaked whales in the MITT Study Area are from a larger global population or a Marianas Islands associated population. NMFS and the Navy are committed to actions that will expand our understanding of beaked whales, including their distribution in the MITT Study Area (see the
Monitoring
and
Adaptive Management
sections below for detailed descriptions). For example, the Navy will co-fund the Pacific Marine Assessment Program for Protected Species (PACMAPPS) survey in spring-summer 2021 to help document beaked whale occurrence, abundance, and distribution in the Mariana Islands. This effort will include deployments of a towed array as well as floating passive acoustic buoys. The Navy will monitor future beaked whale occurrence within select portions of the MITT Study Area starting in 2022. Additionally, the Navy will include Cuvier's beaked whales as a priority species for analysis under a 2020-2023 Navy research-funded program entitled Marine Species Monitoring for Potential Consequences of Disturbance (MSM4PCOD). Finally, the Navy will fund and co-organize with NMFS an expert panel to provide recommendations on scientific data gaps and uncertainties.
Mitigation and Monitoring
Least Practicable Adverse Impact Determination
Comment 26:
A Commenter cited two judicial decisions and commented that the “least practicable adverse impact” standard has not been met. The Commenter stated that contrary to the
Pritzker
Court decision, NMFS, while clarifying that population-level impacts are mitigated “through the application of mitigation measures that limit impacts to individual animals,” has again set population-level impact as the basis for mitigation in the proposed rule. Because NMFS' mitigation analysis is opaque, it is not clear what practical effect this position may have on its rulemaking. The Commenter stated that the proposed rule is also unclear in its application of the “habitat” emphasis in the MMPA's mitigation standard, and that while NMFS' analysis is opaque, its failure to incorporate or even, apparently, to consider viable time-area measures suggests that the agency has not addressed this aspect of the
Pritzker
decision. The Commenter argued that the MMPA sets forth a “stringent standard” for mitigation that requires the agency to minimize impacts to the lowest practicable level, and that the agency must conduct its own analysis and clearly articulate it and not just parrot what the Navy says. The baselessness of this approach can be seen from the outcome of the
Conservation Council
decision, where the parties were able to reach a settlement agreement establishing time-area management measures, among other things, on the Navy's Southern California and Hawaii Range Complexes notwithstanding NMFS' finding, following the Navy, that all such management measures would substantially affect military readiness and were not practicable. Unfortunately, there is no indication in the proposed rule that NMFS has, as yet, done anything different here.
Response:
First, the Commenter's reference to mitigation measures implemented pursuant to a prior settlement agreement is entirely inapplicable to a discussion of NMFS' responsibility to ensure the least practicable adverse impact under the MMPA. Specifically, for those areas that were previously covered under the 2015 settlement agreement for the HSTT Study Area, it is essential to understand that: (1) The measures were developed pursuant to negotiations with the plaintiffs and were specifically not selected and never evaluated based on an examination of the best available science that NMFS otherwise applies to a mitigation assessment and (2) the Navy's agreement to restrictions on its activities as part of a relatively short-term settlement (which did not extend beyond the expiration of the 2013 regulations) did not mean that those restrictions were practicable to implement over the longer term.
Regarding the remainder of the comment, NMFS disagrees with much of what the Commenter asserts. First, we have carefully explained our interpretation of the least practicable adverse impact standard and how it applies to both stocks and individuals, including in the context of the
Pritzker
decision, in the
Mitigation Measures
section. Further, we have applied the standard correctly in this rule in requiring measures that reduce impacts to individual marine mammals in a manner that reduces the probability and/or severity of population-level impacts.
When a suggested or recommended mitigation measure that would reduce impacts is not practicable, NMFS has explored variations of that mitigation to determine if a practicable form of related mitigation exists. This is clearly illustrated in NMFS' independent mitigation analysis process explained in the
Mitigation Measures
section of the final rule. First, some types of mitigation required under this rule are area-specific and vary by mitigation area, demonstrating that NMFS has engaged in a site-specific analysis to ensure mitigation is tailored when practicability demands,
i.e.,
some forms of mitigation were practicable in some areas but not others. For instance, while it was not practicable for the Navy to restrict all use of the Chalan Kanoa Reef and Marpi Reef Geographic Mitigation Areas, NMFS did expand the seaward extent of the areas out to the 400-m isobath. Additionally, while it was not practicable for the Navy to eliminate all training in those two Geographic Mitigation Areas, restrictions in those areas have been expanded such that the Navy will not use explosives year-round and MF1 MFAS will be limited to 20 hours between December 1 and April 30 annually to minimize impacts from sonar on humpback whales during the time when they are engaged in important reproductive behaviors.
Regarding the comment about mitigation of habitat impacts, marine mammal habitat value is informed by marine mammal presence and use and, in some cases, there may be overlap in measures for the species or stock directly and for use of habitat. In this rule, we have required time-area mitigations based on a combination of factors that include higher densities and observations of specific important behaviors of marine mammals themselves, but also that clearly reflect preferred habitat (
e.g.,
reproductive areas of Marpi and Chalan Kanoa Reefs, resting habitat for spinner dolphins in Agat Bay). In addition to being delineated based on physical features that drive habitat function (
e.g.,
bathymetric features), the high densities and concentration of certain important behaviors (
e.g.,
breeding, resting) in these particular areas clearly indicate the presence of preferred habitat. The Commenter seems to suggest that NMFS must always consider separate measures aimed at marine mammal habitat; however, the MMPA does not specify that effects to habitat must be mitigated in separate measures, and NMFS has clearly identified measures that provide significant reduction of impacts to both “marine mammal species and stocks and their habitat,” as required by the statute.
NMFS agrees, however, that the agency must conduct its own analysis, which it has done here, and not just accept what is provided by the Navy. That does not mean, however, that NMFS cannot review the Navy's analysis of effectiveness and practicability of its proposed mitigation measures, which by regulation the Navy was required to submit with its application, and concur with those aspects of the Navy's analysis with which NMFS agrees. The Commenter seems to suggest that NMFS must describe in the rule in detail the rationale for not adopting every conceivable permutation of mitigation, which is neither reasonable nor required by the MMPA. NMFS has described our well-reasoned process for identifying the measures needed to meet the least practicable adverse impact standard in the
Mitigation Measures
section in this rule, and we have followed the approach described there when analyzing potential mitigation for the Navy's activities in the MITT Study Area. Responses to specific recommendations for mitigation measures provided by the Commenter on the proposed rule are discussed separately.
Comment 27:
A Commenter noted that they have previously indicated that, under the least practicable adverse impact requirement, and more generally under the purposes and policies of the MMPA, Congress embraced a policy that minimizes, whenever it is practicable, the risk of killing or seriously injuring a marine mammal incidental to an activity subject to section 101(a)(5)(A), including taking measures in an authorization to eliminate or reduce the
likelihood of lethal taking. Accordingly, the Commenter had recommended that NMFS address this point explicitly in its least practicable adverse impact analysis and clarify whether it agrees that the incidental serious injury or death of a marine mammal always should be considered an adverse impact for purposes of applying the least practicable adverse impact standard. In the preamble to the Atlantic Fleet Training and Testing (AFTT) final rule, NMFS indicated that it was unnecessary or unhelpful to address explicitly the point made by the Commenter that an incidental death or serious injury of a marine mammal should always be considered an adverse impact on the species or stock (83 FR 57117). The Commenter disagrees. The Commenter does not see how NMFS can meet the mandate of the MMPA to reduce adverse impacts to the lowest level practicable if it does not first identify clearly which impacts are adverse and may require mitigation under section 101(a)(5)(A)(i)(II)(aa). The Commenter appreciates NMFS' statement that it has adopted a practice to mitigate mortality to the greatest degree possible, but disagrees with the agency's conclusions that one mortality does not affect the population in a quantifiable or meaningful way. However, the MMPA requires NMFS to go beyond that and reduce any adverse impacts to the greatest extent practicable, even though population-level impacts are not significant.
Response:
NMFS continues to disagree that it is necessary or helpful to explicitly address the point the Commenter raises specifically in the discussion on the least practicable adverse impact standard. It is always NMFS' practice to mitigate serious injury and mortality to the greatest degree possible, as death is the impact that is most easily linked to reducing the probability of adverse impacts to populations. However, we cannot agree that one mortality will always decrease any population in a quantifiable or meaningful way. For example, for very large populations, one mortality may fall well within typical known annual variation and not have any effect on population rates. Mortality is not anticipated or authorized in this rule.
Comment 28:
A Commenter continues to recommend that NMFS clearly separate its application of the least practicable adverse impact requirement from its negligible impact determination. Once NMFS determines that an applicant's proposed activities would have a negligible impact, it still has a responsibility to determine whether the activities would nevertheless have adverse impacts on marine mammal species and stocks and their habitat. If so, NMFS must condition the authorization to eliminate or reduce those impacts whenever, and to the greatest extent, practicable. As the statute is written, it is inappropriate to conflate the two standards, as NMFS seems to be doing.
Response:
NMFS has made clear in this and other rules that the agency separates its application of the least practicable adverse impact requirement in the
Mitigation Measures
section from its negligible impact analyses and determinations for each species or stock in a separate section. Further, NMFS has made this separation clear in practice for years by requiring mitigation measures to reduce impacts to marine mammal species and stocks and their habitat for all projects, even those for which the anticipated take would clearly not approach the negligible impact threshold, even in the absence of mitigation.
Comment 29:
A Commenter recommended that NMFS follow an analysis consisting of three elements to (1) determine whether the impacts of the proposed activities are negligible at the species/stock level, (2) if so, determine whether some of those impacts nevertheless are adverse either to marine mammal species or stocks or key marine mammal habitat, and (3) if so, whether it is practicable for the applicant to reduce or eliminate those impacts through modifying those activities or by other means (
e.g.,
requiring additional mitigation measures to be implemented).
Response:
In the
Mitigation Measures
section of the rule, NMFS has explained in detail our interpretation of the least practicable adverse impact standard, the rationale for our interpretation, and then how we implement the standard. The method the agency is using addresses all of the necessary components of the standard and produces effective mitigation measures that result in the least practicable adverse impact on both the species or stocks and their habitat. The Commenter has failed to illustrate why NMFS' approach is inadequate or why the Commenter's proposed approach would be better, and we therefore decline to accept the recommendation.
Comment 30:
Regarding the habitat component of the least practicable adverse impact standard, a Commenter recommends that NMFS (1) adopt a clear decision-making framework that recognizes the species and stock component
and
the marine mammal habitat component of the least practicable adverse impact provision and (2) always consider whether there are potentially adverse impacts on marine mammal habitat and whether it is practicable to minimize them. The MMPA requires that NMFS address both types of impacts, not that there be no overlap between the mitigation measures designed to reduce those impacts.
Response:
NMFS' decision-making framework for applying the least practicable adverse impact standard clearly recognizes the habitat component of the provision (see
Mitigation Measures
section of the rule). NMFS does always consider whether there are adverse impacts on habitat and how they can be mitigated. Marine mammal habitat value is informed by marine mammal presence and use and, in some cases, there may be overlap in measures for the species or stock directly and for use of habitat. In this rule, we have required time-area mitigation measures based on a combination of factors that include higher densities and observations of specific important behaviors of marine mammal species themselves, but also that clearly reflect preferred habitat (
e.g.,
reproductive habitat off Marpi and Chalan Kanoa Reefs and resting habitat in Agat Bay). In addition to being delineated based on physical features that drive habitat function (
e.g.,
bathymetric features), the high densities and concentration of certain important behaviors (
e.g.,
reproduction, feeding, resting) in these particular areas clearly indicate the presence of preferred habitat. The Commenter seems to suggest that NMFS must include mitigation measures aimed at marine mammal habitat that are wholly separate from addressing adverse impacts directly on the species or stocks. However, the MMPA does not specify that effects to habitat must be mitigated in separate measures, and NMFS has clearly included measures that provide significant reduction of impacts to both marine mammal species or stocks and their habitat, as required by the statute.
Comment 31:
A Commenter recommended that NMFS rework its evaluation criteria for applying the least practicable adverse impact standard to separate the factors used to determine whether a potential impact on marine mammals or their habitat is adverse and whether possible mitigation measures would be effective.
Response:
In the
Mitigation Measures
section, NMFS has explained in detail our interpretation and application of the least practicable adverse impact standard. The Commenter has recommended an alternate way of
interpreting and implementing the least practicable adverse impact standard, in which NMFS would consider the effectiveness of a measure in our evaluation of its practicability. The Commenter erroneously asserts that NMFS currently considers the effectiveness of a measure in a determination of whether the potential effects of an activity are adverse, but the Commenter has misunderstood NMFS' practice—rather, NMFS appropriately considers the effectiveness of a measure in the evaluation of the degree to which a measure will reduce adverse impacts on marine mammal species or stocks and their habitat, as a
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