Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Hawaii-Southern California Training and Testing Study Area

Federal RegisterSep 13, 2019

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[190826-0018 ]

RIN 0648-BJ06

Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Hawaii-Southern California Training and Testing Study Area

AGENCY:

National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION:

Proposed rule; request for comment.

SUMMARY:

NMFS has received a request from the U.S. Navy (Navy) to extend the time period from December 2023 to December 2025 for Marine Mammal Protection Act (MMPA) regulations authorizing the take of marine mammals incidental to Navy training and testing activities conducted in the Hawaii-Southern California Training and Testing (HSTT) Study Area. In August 2018, the MMPA was amended by the John S. McCain National Defense Authorization Act (NDAA) for Fiscal Year 2019 to allow for 7-year authorizations for military readiness activities, as compared to the previously allowed five years. The Navy's activities qualify as military readiness activities pursuant to the MMPA as amended by the NDAA for Fiscal Year 2004. In making the request to extend the time period covered by the MMPA HSTT regulations from five to seven years, the Navy proposes no changes to their specified activities, the geographical region in which those activities would be conducted, mitigation measures, monitoring, or reporting over the longer seven-year period. Pursuant to the MMPA, NMFS is requesting comments on the proposed seven-year rule and associated Letters of Authorization (LOAs) to cover the same activities covered by the existing 2018 HSTT regulations. NMFS will consider all public comments prior to issuing any final rule and making final decisions on the issuance of the requested LOAs, and agency responses will be summarized in the notice of the final decision.

DATES:

Comments and information must be received no later than October 15, 2019.

ADDRESSES:

You may submit comments on this document, identified by NOAA-NMFS-2019-0103, by any of the following methods:

•

Electronic submission:

Submit all electronic public comments via the federal e-Rulemaking Portal. Go to

www.regulations.gov/#!docketDetail;D=NOAA-NMFS-2019-0103,

click the “Comment Now!” icon, complete the required fields, and enter or attach your comments.

•

Mail:

Submit written comments to Jolie Harrison, Chief, Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East West Highway, Silver Spring, MD 20910.

Instructions:

Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on

www.regulations.gov

without change. All personal identifying information (

e.g.,

name, address), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous). Attachments to electronic comments will be accepted in Microsoft Word, Excel, or Adobe PDF file formats only.

A copy of the Navy's applications, NMFS' proposed and final rules and subsequent LOAs 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:

Wendy Piniak, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose of Regulatory Action

These proposed regulations, issued under the authority of the MMPA (16 U.S.C. 1361

et seq.

), would extend 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, in-water detonations, air guns, impact pile driving/vibratory extraction, and the movement of vessels throughout the HSTT Study Area. The HSTT Study Area is comprised of established operating and warning areas across the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line. The Study Area includes the at-sea areas of three existing range complexes (the Hawaii Range Complex, the Southern California (SOCAL) Range Complex, and the Silver Strand Training Complex), and overlaps a portion of the Point Mugu Sea Range (PMSR). Also included in the Study Area are Navy pierside locations in Hawaii and Southern California, Pearl Harbor, San Diego Bay, and the transit corridor on the high seas where sonar training and testing may occur.

NMFS received an application from the Navy requesting to extend NMFS' existing MMPA regulations (50 CFR part 218, subpart H; hereafter “2018 HSTT regulations”) that authorize the take of marine mammals incidental to Navy training and testing activities conducted in the HSTT Study Area to cover seven years of the Navy's activities, instead of five. Take is anticipated to occur by Level A harassment and Level B harassment as well as a very small number of serious injuries or mortalities incidental to the Navy's training and testing activities.

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, the public is provided with notice of the proposed incidental take authorization the opportunity to review and 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

Preliminary Analysis and Negligible Impact Determination

section below discusses the definition of “negligible impact.”

The NDAA for Fiscal Year 2004 (2004 NDAA) (Pub. L. 108-136) amended section 101(a)(5) of the MMPA to remove the “small numbers” and “specified geographical region” provisions indicated above and amended the definition of “harassment” as it applies to a “military readiness activity” to read as follows (Section 3(18)(B) of the MMPA): (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 least practicable adverse impact 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 of Request

On December 27, 2018, NMFS issued a five-year final rule governing the taking of marine mammals incidental to Navy training and testing activities conducted in the HSTT Study Area (83 FR 66846; hereafter “2018 HSTT final rule”). Previously on August 13, 2018, and towards the end of the time period in which NMFS was processing the Navy's request for the 2018 regulations, the 2019 NDAA amended the MMPA for military readiness activities to allow incidental take regulations to be issued for up to seven years instead of the previous five years. The Navy's training and testing activities conducted in the HSTT Study Area qualify as military readiness activities pursuant to the MMPA, as amended by the 2004 NDAA. On March 11, 2019 the Navy submitted an application requesting that NMFS extend the 2018 HSTT regulations and associated LOAs such that they would cover take incidental to seven years of training and testing activities instead of five, extending the expiration date from December 20, 2023 to December 20, 2025.

In its 2019 application, the Navy proposes no changes to the nature of the specified activities covered by the 2018 HSTT final rule, the level of activity within and between years would be consistent with that previously analyzed in the 2018 HSTT final rule, and all activities would be conducted within the same boundaries of the HSTT Study Area identified in the 2018 HSTT final rule. Therefore, the training and testing activities (

e.g.,

equipment and sources used, exercises conducted) and the mitigation, monitoring, and nearly all reporting measures are identical to those described and analyzed in the 2018 HSTT final rule. The only changes included in the Navy's request are to conduct those same activities in the same region for an additional two years. In its request, the Navy included all information necessary to identify the type and amount of incidental take that may occur in the two additional years so NMFS could determine whether the analyses and conclusions regarding the impacts of the proposed activities on marine mammal species and stocks previously reached for five years of activities remain the same for seven years of identical activity.

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 ensures the readiness of the naval forces of the United States. The Navy executes this responsibility by establishing and executing training programs, including at-sea training and exercises, and ensuring naval forces have access to the ranges, operating areas (OPAREAs), and airspace needed to develop and maintain skills for conducting naval activities.

The Navy proposes to continue conducting training and testing activities within the HSTT Study Area. The Navy's March 11, 2019, rulemaking and LOA extension application (hereafter “2019 Navy application”) reflects the same compilation of training and testing activities presented in the Navy's October 13, 2017, initial rulemaking and LOA application (hereafter “2017 Navy application”) and the 2018 HSTT regulations that were subsequently promulgated, which can be found at:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

These activities are deemed by the Navy necessary to accomplish military readiness requirements and are anticipated to continue into the reasonably foreseeable future. The 2019 Navy application and this rule cover training and testing activities that would occur over seven years, including the five years already authorized under the 2018 HSTT regulations, with the regulations valid from the publication date of the final rule (if issued) through December 20, 2025.

Summary of the Proposed Regulations

NMFS is proposing to extend the incidental take regulations and associated LOAs through December 20, 2025, to cover the same Navy activities covered by the 2018 HSTT regulations. The 2018 HSTT final rule was only recently published and its analysis remains current and valid. In its 2019 application, the Navy proposes no changes to the nature (

e.g.,

equipment and sources used, exercises conducted) or level of the specified activities within or between years or to the boundaries of the HSTT Study Area. The mitigation, monitoring, and nearly all reporting measures (described below) would be identical to those described and analyzed in the 2018 HSTT final rule. The proposed regulatory language included at the end of this proposed rule, which would be published at 50 CFR part 218, subpart H, also is the same as that under the HSTT 2018 regulations, except for a small number of technical changes. No new information has been received from the Navy, or otherwise become available to NMFS, since publication of the 2018 HSTT final rule that significantly changes the analyses supporting the 2018 findings. Where there is any new information pertinent to the descriptions, analyses, or findings required to authorize incidental take for military readiness activities under MMPA section 101(a)(5)(A), that information is provided in the appropriate sections below.

Because the activities included in the 2019 Navy application have not changed and the analyses and findings included in the documents provided and produced in support of the recently published 2018 HSTT final rule remain current and applicable, this proposed rule relies heavily on and references to the applicable information and analyses

in those documents. Below is a list of the regulatory documents referenced in this proposed rule. The list indicates the short name by which the document is referenced in this proposed rule, as well as the full titles of the cited documents. All of the documents can be found at:

www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities

and

http://www.hstteis.com/

• NMFS June 26, 2018, Hawaii-Southern California Training and Testing (HSTT) proposed rule (83 FR 29872; hereafter “2018 HSTT proposed rule”);

• NMFS December 27, 2018, Hawaii-Southern California Training and Testing (HSTT) final rule (83 FR 66846; hereafter “2018 HSTT final rule”);

• Navy October 13, 2017, MMPA rulemaking and LOA application (hereafter “2017 Navy application”);

• Navy March 11, 2019, MMPA rulemaking and LOA extension application (hereafter “2019 Navy application”); and

• October 26, 2018, Hawaii-Southern California Training and Testing (HSTT) Final Environmental Impact Statement/Overseas Environmental Impact Statement (FEIS/OEIS) (hereafter “2018 HSTT FEIS/OEIS”).

Description of the Specified Activity

The Navy requests authorization to take marine mammals incidental to conducting training and testing activities. The Navy has determined that acoustic and explosives stressors are most likely to result in impacts on marine mammals that could rise to the level of harassment. Detailed descriptions of these activities are provided in Chapter 2 of the 2018 HSTT FEIS/OEIS and in the 2017 and 2019 Navy applications.

Overview of Training and Testing Activities

The Navy routinely trains in the HSTT Study Area in preparation for national defense missions. Training and testing activities and components covered in the 2019 Navy application are described in detail in the

Overview of Training and Testing Activities

sections of the 2018 HSTT proposed rule, the 2018 HSTT final rule, and Chapter 2 (

Description of Proposed Action and Alternatives

) of the 2018 HSTT FEIS/OEIS (

http://www.hstteis.com/

). Each military training and testing activity described meets mandated Fleet requirements to deploy ready forces. The Navy proposes no changes to the specified activities described and analyzed in the 2018 HSTT final rule. The boundaries of the HSTT Study Area (see Figure 2-1 of the 2019 Navy application); the training and testing activities (

e.g.,

equipment and sources used, exercises conducted); manner of or amount of vessel movement; and standard operating procedures presented in this proposed rule are identical to those described and analyzed in the 2018 HSTT final rule.

Dates and Duration

The specified activities would occur at any time during the seven-year period of validity of the regulations. The proposed number of training and testing activities are described in the

Detailed Description of the Specified Activities

section (Tables 1 through 9).

Specified Geographical Region

The Navy proposes no changes to the geographic extent of the HSTT Study Area as described in the 2018 HSTT final rule. The HSTT Study Area (see Figure 2-1 of the 2019 Navy application) is comprised of established operating and warning areas across the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line. The Study Area includes the at-sea areas of three existing range complexes (the Hawaii Range Complex, the Southern California (SOCAL) Range Complex, and the Silver Strand Training Complex), and overlaps a portion of the Point Mugu Sea Range (PMSR). Also included in the Study Area are Navy pierside locations in Hawaii and Southern California, Pearl Harbor, San Diego Bay, and the transit corridor

on the high seas where sonar training and testing may occur.

Vessel transit corridors are the routes typically used by Navy assets to traverse from one area to another. The route depicted in Figure 2-1 of the 2019 Navy application is the shortest route between Hawaii and Southern California, making it the quickest and most fuel efficient. The depicted vessel transit corridor is notional and may not represent the actual routes used by ships and submarines transiting from Southern California to Hawaii and back. Actual routes navigated are based on a number of factors including, but not limited to, weather, training, and operational requirements.

A Navy range complex consists of geographic areas that encompass a water component (above and below the surface) and airspace, and may encompass a land component where training and testing of military platforms, tactics, munitions, explosives, and electronic warfare systems occur. Range complexes include established OPAREAs, which may be further divided to provide better control of the area for safety reasons. Additional detail on range complexes and testing ranges was provided in the

Duration and Location

section of the 2018 HSTT proposed rule; please see the 2018 HSTT proposed rule or the 2017 Navy application for more information and maps.

Description of Acoustic and Explosive 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 specific components that could act as stressors by having direct or indirect impacts on the environment are described in detail in the

Description of Acoustic and Explosive Stressors

section of the 2018 HSTT final rule and Chapter 2 (

Description of Proposed Action and Alternatives

) of the 2018 HSTT FEIS/OEIS. The Navy proposes no changes to the nature of the specified activities and, therefore, the acoustic and explosive stressors are identical to those described and analyzed in the 2018 HSTT final rule.

Other Stressor—Vessel Strike

Vessel strikes are not specific to any particular training or testing activity, but rather a limited, sporadic, and incidental result of Navy vessel movement within the HSTT Study Area. Navy vessels transit at speeds that are optimal for fuel conservation or to meet training and testing requirements. The average speed of large Navy ships ranges between 10 and 15 knots and submarines generally operate at speeds in the range of 8-13 knots, while a few specialized vessels can travel at faster speeds. By comparison, this is slower than most commercial vessels where full speed for a container ship is typically 24 knots (Bonney and Leach, 2010).

Should a vessel strike occur, it would likely result in incidental take from serious injury and/or mortality and, accordingly, for the purposes of the analysis we assume that any ship strike would result in serious injury or mortality. The Navy proposes no changes to the nature of the specified activities, the training and testing activities, the manner of or amount of vessel movement, or standard operating procedures described in the 2018 HSTT final rule. Therefore, the description of vessel strikes as a stressor is the same as those presented in the

Other Stressor—Vessel Strike

sections of the 2018 HSTT proposed rule and 2018 HSTT final rule.

Detailed Description of the Specified Activities

The Navy's proposed activities are presented and analyzed as a representative year of training to account for the natural fluctuation of training cycles and deployment schedules in any seven-year period. In the 2018 HSTT final rule, NMFS analyzed the potential impacts of these activities (

i.e.,

incidental take of marine mammals) based on the Navy conducting three years of a representative level of activity and two years of a maximum level of activity. For the purposes of this rulemaking and analyzing potential impacts to marine mammals, the Navy proposes that the additional two years of training and testing would consist of one additional year of maximum training tempo and one representative year of training tempo consistent with the pattern set forth in the 2018 HSTT final rule, the 2018 HSTT FEIS/OEIS, and the 2017 Navy application.

Proposed Training Activities

The number of proposed training activities that could occur annually and the duration of those activities remains identical to those presented in Table 4 of the 2018 HSTT final rule, and are not repeated here. The number of proposed training activities that could occur over the seven-year period are presented in Table 1. The table is organized according to primary mission areas and includes the activity name, associated stressors applicable to these proposed regulations, sound source bin, number of proposed activities, and locations of those activities in the HSTT Study Area. For further information regarding the primary platform used (

e.g.,

ship or aircraft type) see Appendix A (

Navy Activity Descriptions

) of the 2018 HSTT FEIS/OEIS.

Table 1—Proposed Training Activities Analyzed for Seven-Year Period in the HSTT Study Area

Stressor category

Activity name

Description

Source bin

Location

7-Year

number

of events

Major Training Events—Large Integrated Anti-Submarine Warfare

Acoustic

Composite Training Unit Exercise

Aircraft carrier and carrier air wing integrates with surface and submarine units in a challenging multi-threat operational environment that certifies them ready to deploy

ASW1, ASW2, ASW3, ASW4, ASW5, HF1, LF6, MF1, MF3, MF4, MF5, MF11, MF12

SOCAL

Acoustic

Rim of the Pacific Exercise

A biennial multinational training exercise in which navies from Pacific Rim nations and the United Kingdom assemble in Pearl Harbor, Hawaii, to conduct training throughout the Hawaiian Islands in a number of warfare areas. Marine mammal systems may be used during a Rim of the Pacific exercise. Components of a Rim of the Pacific exercise, such as certain mine warfare and amphibious training, may be conducted in the Southern California Range Complex

ASW2, ASW3, ASW4, HF1, HF3, HF4, M3, MF1, MF3, MF4, MF5, MF11

HRC

SOCAL

Major Training Events—Medium Integrated Anti-Submarine Warfare

Acoustic

Fleet Exercise/Sustainment Exercise

Aircraft carrier and carrier air wing integrates with surface and submarine units in a challenging multi-threat operational environment to maintain ability to deploy

ASW1, ASW2, ASW3, ASW4, HF1, LF6, MF1, MF3, MF4, MF5, MF11, MF12

HRC

SOCAL

Acoustic

Undersea Warfare Exercise

Elements of the anti-submarine warfare tracking exercise combine in this exercise of multiple air, surface, and subsurface units, over a period of several days. Sonobuoys are released from aircraft. Active and passive sonar used

ASW3, ASW4, HF1, LF6, MF1, MF3, MF4, MF5, MF11, MF12

HRC

Integrated/Coordinated Training—Small Integrated Anti-Submarine Warfare Training

Acoustic

Navy Undersea Warfare Training and Assessment Course Surface Warfare Advanced Tactical Training

Multiple ships, aircraft, and submarines integrate the use of their sensors to search for, detect, classify, localize, and track a threat submarine in order to launch an exercise torpedo

ASW3, ASW4, HF1, MF1, MF3, MF4, MF5

HRC

SOCAL

Integrated/Coordinated Training—Medium Coordinated Anti-Submarine Warfare Training

Acoustic

Submarine Commanders Course

Train prospective submarine Commanding Officers to operate against surface, air, and subsurface threats

ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, TORP1, TORP2

HRC

SOCAL

Integrated/Coordinated Training—Small Coordinated Anti-Submarine Warfare Training

Acoustic

Amphibious Ready Group/Marine Expeditionary Unit Exercise Group Sail Independent Deployer Certification Exercise/Tailored Anti-Submarine Warfare Training

Small-scale, short duration, coordinated anti-submarine warfare exercises

ASW2, ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, MF11

HRC

SOCAL

Amphibious Warfare

Explosive

Naval Surface Fire Support Exercise—at Sea

Surface ship uses large-caliber gun to support forces ashore; however, land target simulated at sea. Rounds impact water and are scored by passive acoustic hydrophones located at or near target area

Large-caliber HE rounds (E5)

HRC (W188)

105

Acoustic

Amphibious Marine Expeditionary Unit Exercise

Navy and Marine Corps forces conduct advanced integration training in preparation for deployment certification

ASW2, ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, MF11

SOCAL

Acoustic

Amphibious Marine Expeditionary Unit Integration Exercise

Navy and Marine Corps forces conduct integration training at sea in preparation for deployment certification

ASW2, ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, MF11

SOCAL

Acoustic

Marine Expeditionary Unit Composite Training Unit Exercise

Amphibious Ready Group exercises are conducted to validate the Marine Expeditionary Unit's readiness for deployment and includes small boat raids; visit, board, search, and seizure training; helicopter and mechanized amphibious raids; and a non-combatant evacuation operation

ASW2, ASW3, ASW4, HF1, MF1, MF3, MF4, MF5, MF11

SOCAL

Anti-Submarine Warfare

Acoustic

Anti-Submarine Warfare Torpedo Exercise—Helicopter

Helicopter crews search for, track, and detect submarines. Recoverable air launched torpedoes are employed against submarine targets

MF4, MF5, TORP1

HRC

SOCAL

728

Acoustic

Anti-Submarine Warfare Torpedo Exercise—Maritime Patrol Aircraft

Maritime patrol aircraft crews search for, track, and detect submarines. Recoverable air launched torpedoes are employed against submarine targets

MF5, TORP1

HRC

SOCAL

175

Acoustic

Anti-Submarine Warfare Torpedo Exercise—Ship

Surface ship crews search for, track, and detect submarines. Exercise torpedoes are used during this event

ASW3, MF1, TORP1

HRC

SOCAL

350

819

Acoustic

Anti-Submarine Warfare Torpedo Exercise—Submarine

Submarine crews search for, track, and detect submarines. Exercise torpedoes are used during this event

ASW4, HF1, MF3, TORP2

HRC

SOCAL

336

Acoustic

Anti-Submarine Warfare Tracking Exercise—Helicopter

Helicopter crews search for, track, and detect submarines

MF4, MF5

HRC

SOCAL, PMSR

HSTT Transit Corridor

1,113

3,668

Acoustic

Anti-Submarine Warfare Tracking Exercise—Maritime Patrol Aircraft

Maritime patrol aircraft aircrews search for, track, and detect submarines. Recoverable air launched torpedoes are employed against submarine targets

MF5

HRC

SOCAL, PMSR

182

350

Acoustic

Anti-Submarine Warfare Tracking Exercise—Ship

Surface ship crews search for, track, and detect submarines

ASW3, MF1, MF11, MF12

HRC

SOCAL, PMSR

1,568

2,961

Acoustic

Anti-Submarine Warfare Tracking Exercise—Submarine

Submarine crews search for, track, and detect submarines

ASW4, HF1, HF3, MF3

HRC

SOCAL, PMSR

HSTT Transit Corridor

1,400

350

Explosive, Acoustic

Service Weapons Test

Air, surface, or submarine crews employ explosive torpedoes against virtual targets

HF1, MF3, MF6, TORP2, Explosive torpedoes (E11)

HRC

SOCAL

Mine Warfare

Acoustic

Airborne Mine Countermeasure—Mine Detection

Helicopter aircrews detect mines using towed or laser mine detection systems

HF4

SOCAL

Explosive, Acoustic

Civilian Port Defense—Homeland Security Anti-Terrorism/Force Protection Exercises

Maritime security personnel train to protect civilian ports against enemy efforts to interfere with access to those ports

HF4, SAS2, E2, E4

Pearl Harbor, HI

San Diego, CA

Explosive

Marine Mammal Systems

The Navy deploys trained bottlenose dolphins (

Tursiops truncatus

) and California sea lions (

Zalophus californianus

) as part of the marine mammal mine-hunting and object-recovery system

HRC

SOCAL

1,225

Acoustic

Mine Countermeasure Exercise—Ship Sonar

Ship crews detect and avoid mines while navigating restricted areas or channels using active sonar

HF4, HF8, MF1K

HRC

SOCAL

210

664

Acoustic

Mine Countermeasure Exercise—Surface

Mine countermeasure ship crews detect, locate, identify, and avoid mines while navigating restricted areas or channels, such as while entering or leaving port

HF4

SOCAL

1,862

Explosive, Acoustic

Mine Countermeasures Mine Neutralization Remotely Operated Vehicle

Ship, small boat, and helicopter crews locate and disable mines using remotely operated underwater vehicles

HF4, E4

HRC

SOCAL

2,604

Explosive

Mine Neutralization Explosive Ordnance Disposal

Personnel disable threat mines using explosive charges

E4, E5, E6, E7

HRC (Puuloa)

SOCAL (IB, TAR 2, TAR 3, TAR 21, SWAT 3, SOAR)

140

1,358

Acoustic

Submarine Mine Exercise

Submarine crews practice detecting mines in a designated area

HF1

HRC

SOCAL

280

Acoustic

Surface Ship Object Detection

Ship crews detect and avoid mines while navigating restricted areas or channels using active sonar

MF1K, HF8

HRC

SOCAL

287

1,134

Explosive

Underwater Demolitions Multiple Charge—Mat Weave and Obstacle Loading

Military personnel use explosive charges to destroy barriers or obstacles to amphibious vehicle access to beach areas

E10, E13

SOCAL (TAR 2, TAR 3)

126

Explosive

Underwater Demolition Qualification and Certification

Navy divers conduct various levels of training and certification in placing underwater demolition charges

E6, E7

HRC (Puuloa)

SOCAL (TAR 2)

203

700

Surface Warfare

Explosive

Bombing Exercise Air-to-Surface

Fixed-wing aircrews deliver bombs against surface targets

E12

HRC

SOCAL

HSTT Transit Corridor

1309

4480

Explosive

Gunnery Exercise Surface-to-Surface Boat Medium-Caliber

Small boat crews fire medium-caliber guns at surface targets

E1, E2

HRC

SOCAL

Explosive

Gunnery Exercise Surface-to-Surface Ship Large-caliber

Surface ship crews fire large-caliber guns at surface targets

HRC

SOCAL

HSTT Transit Corridor

210

1,302

Explosive

Gunnery Exercise Surface-to-Surface Ship Medium-Caliber

Surface ship crews fire medium-caliber guns at surface targets

E1, E2

HRC

SOCAL

HSTT Transit Corridor

350

1,260

280

Explosive, Acoustic

Independent Deployer Certification Exercise/Tailored Surface Warfare Training

Multiple ships, aircraft and submarines conduct integrated multi-warfare training with a surface warfare emphasis. Serves as a ready-to-deploy certification for individual surface ships tasked with surface warfare missions

E1, E3, E6, E10

SOCAL

Explosive

Integrated Live Fire Exercise

Naval Forces defend against a swarm of surface threats (ships or small boats) with bombs, missiles, rockets, and small-, medium- and large-caliber guns

E1, E3, E6, E10

HRC (W188A)

SOCAL (SOAR)

Explosive

Missile Exercise Air-to-Surface

Fixed-wing and helicopter aircrews fire air-to-surface missiles at surface targets

E6, E8, E10

HRC

SOCAL

1,498

Explosive

Missile Exercise Air-to-Surface Rocket

Helicopter aircrews fire both precision-guided and unguided rockets at surface targets

HRC

SOCAL

1,598

1,722

Explosive

Missile Exercise Surface-to-Surface

Surface ship crews defend against surface threats (ships or small boats) and engage them with missiles

E6, E10

HRC (W188)

SOCAL (W291)

140

Explosive, Acoustic

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 munitions

TORP2, E5, E10, E12

HRC

SOCAL

Pile driving

Elevated Causeway System

A pier is constructed off of the beach. Piles are driven into the bottom with an impact hammer. Piles are removed from seabed via vibratory extractor. Only in-water impacts are analyzed

Impact hammer or vibratory extractor

SOCAL

Other Training Exercises

Acoustic

Kilo Dip

Functional check of the dipping sonar prior to conducting a full test or training event on the dipping sonar

MF4

HRC

SOCAL

420

16,800

Acoustic

Submarine Navigation Exercise

Submarine crews operate sonar for navigation and object detection while transiting into and out of port during reduced visibility

HF1, MF3

Pearl Harbor, HI

San Diego Bay, CA

1,540

560

Acoustic

Submarine Sonar Maintenance and Systems Checks

Maintenance of submarine sonar systems is conducted pierside or at sea

MF3

HRC

Pearl Harbor, HI

SOCAL

San Diego Bay, CA

HSTT Transit Corridor

1,820

651

644

Acoustic

Submarine Under-Ice Certification

Submarine crews train to operate under ice. Ice conditions are simulated during training and certification events

HF1

HRC

SOCAL

Acoustic

Surface Ship Sonar Maintenance and Systems Checks

Maintenance of surface ship sonar systems is conducted pierside or at sea

HF8, MF1

HRC

Pearl Harbor, HI

SOCAL

San Diego, CA

HSTT Transit Corridor

525

560

1,750

Acoustic

Unmanned Underwater Vehicle Training—Certification and Development

Unmanned underwater vehicle certification involves training with unmanned platforms to ensure submarine crew proficiency. Tactical development involves training with various payloads for multiple purposes to ensure that the systems can be employed effectively in an operational environment

FLS2, M3, SAS2

HRC

SOCAL

175

Notes:

HRC = Hawaii Range Complex, SOCAL = Southern California Range Complex, HSTT = Hawaii-Southern California Training and Testing, PMSR = Point Mugu Sea Range Overlap, TAR = Training Area and Range, SOAR = Southern California Anti-Submarine Warfare Range, IB = Imperial Beach Minefield.

Any non-antisubmarine warfare activity that could occur is captured in the individual activities.

For the Bombing Exercise Air-to-Surface, all activities were analyzed using E12 explosive bin, but smaller explosives are frequently used.

Proposed Testing Activities

The number of proposed testing activities that could occur annually and the duration of those activities are identical to those presented in Tables 5 through 8 of the 2018 HSTT final rule, and are not repeated here. Similar to the 2017 Navy application, the Navy's proposed testing activities here are based on the level of testing activities anticipated to be conducted into the reasonably foreseeable future, with adjustments that account for changes in the types and tempo (increases or decreases) of testing activities to meet current and future military readiness requirements. The number of proposed testing activities that could occur for the seven-year period are presented in Tables 2 through 5.

Naval Air Systems Command

The proposed Naval Air Systems Command testing activities that could occur over the seven-year period within the HSTT Study Area are presented in Table 2.

Table 2—Proposed Naval Air Systems Command Testing Activities Analyzed for Seven-Year Period in the HSTT Study Area

Stressor category

Activity name

Description

Source bin

Location

7-Year

number

of events

Anti-Submarine Warfare

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

MF5, TORP1

HRC

SOCAL

134

353

Explosive, Acoustic

Anti-Submarine Warfare Tracking Test—Helicopter

This event is similar to the training event anti-submarine tracking exercise—helicopter. The test evaluates the sensors and systems used to detect and track submarines and to ensure that helicopter systems used to deploy the tracking systems perform to specifications

MF4, MF5, E3

SOCAL

414

Explosive, Acoustic

Anti-Submarine Warfare Tracking Test—Maritime Patrol Aircraft

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

ASW2, ASW5, MF5, MF6, E1, E3

HRC

SOCAL

399

436

Explosive, Acoustic

Sonobuoy Lot Acceptance Test

Sonobuoys are deployed from surface vessels and aircraft to verify the integrity and performance of a lot or group of sonobuoys in advance of delivery to the fleet for operational use

ASW2, ASW5, HF5, HF6, LF4, MF5, MF6, E1, E3, E4

SOCAL

1,120

Mine Warfare

Acoustic

Airborne Dipping Sonar Minehunting Test

A mine-hunting dipping sonar system that is deployed from a helicopter and uses high-frequency sonar for the detection and classification of bottom and moored mines

HF4

SOCAL

Explosive

Airborne Mine Neutralization System Test

A test of the airborne mine neutralization system that evaluates the system's ability to detect and destroy mines from an airborne mine countermeasures capable helicopter (

e.g.,

MH-60). The airborne mine neutralization system uses up to four unmanned underwater vehicles equipped with high-frequency sonar, video cameras, and explosive and non-explosive neutralizers

SOCAL

117

Acoustic

Airborne Sonobuoy Minehunting Test

A mine-hunting system made up of sonobuoys deployed from a helicopter. A field of sonobuoys, using high-frequency sonar, is used for detection and classification of bottom and moored mines

HF6

SOCAL

Surface Warfare

Explosive

Air-to-Surface Bombing Test

This event is similar to the training event bombing exercise air-to-surface. Fixed-wing aircraft test the delivery of bombs against surface maritime targets with the goal of evaluating the bomb, the bomb carry and delivery system, and any associated systems that may have been newly developed or enhanced

HRC

SOCAL

Explosive

Air-to-Surface Gunnery Test

This event is similar to the training event gunnery exercise air-to-surface. Fixed-wing and rotary-wing aircrews evaluate new or enhanced aircraft guns against surface maritime targets to test that the gun, gun ammunition, or associated systems meet required specifications or to train aircrew in the operation of a new or enhanced weapons system

HRC

SOCAL

330

Explosive

Air-to-Surface Missile Test

This event is similar to the training event missile exercise air-to-surface. Test may involve both fixed-wing and rotary-wing aircraft launching missiles at surface maritime targets to evaluate the weapons system or as part of another systems integration test

E6, E9, E10

HRC

SOCAL

126

384

Explosive

Rocket Test

Rocket tests are conducted to evaluate the integration, accuracy, performance, and safe separation of guided and unguided 2.75-inch rockets fired from a hovering or forward flying helicopter or tilt rotor aircraft

HRC

SOCAL

142

Other Testing Activities

Acoustic

Kilo Dip

Functional check of a helicopter deployed dipping sonar system (

e.g.,

AN/AQS-22) prior to conducting a testing or training event using the dipping sonar system

MF4

SOCAL

Acoustic

Undersea Range System Test

Post installation node survey and test and periodic testing of range node transmit functionality

MF9

HRC

129

Notes:

HRC = Hawaii Range Complex, SOCAL = Southern California Range Complex.

Naval Sea Systems Command

The proposed Naval Sea Systems Command testing activities that could occur over the seven-year period within the HSTT Study Area are presented in Table 3.

Table 3—Proposed Naval Sea Systems Command Testing Activities Analyzed for Seven-Year Period in the HSTT Study Area

Stressor category

Activity name

Description

Source bin

Location

7-Year

number of events

Anti-Submarine Warfare

Acoustic

Anti-Submarine Warfare Mission Package Testing

Ships and their supporting platforms (

e.g.,

rotary-wing aircraft and unmanned aerial systems) detect, localize, and prosecute submarines

ASW1, ASW2, ASW3, ASW5, MF1, MF4, MF5, MF12, TORP1

HRC

SOCAL

154

161

Acoustic

At-Sea Sonar Testing

At-sea testing to ensure systems are fully functional in an open ocean environment

ASW3, ASW4, HF1, LF4, LF5, M3, MF1, MF1K, MF2, MF3, MF5, MF9, MF10, MF11

HRC

HRC-SOCAL

SOCAL

109

138

Acoustic

Countermeasure Testing

Countermeasure testing involves the testing of systems that will detect, localize, and track incoming weapons, including marine vessel targets. Testing includes surface ship torpedo defense systems and marine vessel stopping payloads

ASW3, ASW4, HF5, TORP1, TORP2

HRC

HRC-SOCAL

SOCAL

HSTT Transit Corridor

Acoustic

Pierside Sonar Testing

Pierside testing to ensure systems are fully functional in a controlled pierside environment prior to at-sea test activities

HF1, HF3, HF8, M3, MF1, MF3, MF9

Pearl Harbor, HI

San Diego, CA

Acoustic

Submarine Sonar Testing/Maintenance

Pierside and at-sea testing of submarine systems occurs periodically following major maintenance periods and for routine maintenance

HF1, HF3, M3, MF3

HRC

Pearl Harbor, HI

San Diego, CA

119

168

Acoustic

Surface Ship Sonar Testing/Maintenance

Pierside and at-sea testing of ship systems occurs periodically following major maintenance periods and for routine maintenance

ASW3, MF1, MF1K, MF9, MF10

HRC

Pearl Harbor, HI

San Diego, CA

SOCAL

Explosive, Acoustic

Torpedo (Explosive) Testing

Air, surface, or submarine crews employ explosive and non-explosive torpedoes against artificial targets

ASW3, HF1, HF5, HF6, MF1, MF3, MF4, MF5, MF6, TORP1, TORP2, E8, E11

HRC (W188)

HRC (W188) SOCAL

SOCAL

Acoustic

Torpedo (Non-Explosive) Testing

Air, surface, or submarine crews employ non-explosive torpedoes against submarines or surface vessels

ASW3, ASW4, HF1, HF6, M3, MF1, MF3, MF4, MF5, MF6, TORP1, TORP2, TORP3

HRC

HRC SOCAL

SOCAL

Mine Warfare

Explosive, Acoustic

Mine Countermeasure and Neutralization Testing

Air, surface, and subsurface vessels neutralize threat mines and mine-like objects

HF4, E4

SOCAL

Explosive, Acoustic

Mine Countermeasure Mission Package Testing

Vessels and associated aircraft conduct mine countermeasure operations

HF4, SAS2, E4

HRC

SOCAL

118

406

Acoustic

Mine Detection and Classification Testing

Air, surface, and subsurface vessels detect and classify mines and mine-like objects. Vessels also assess their potential susceptibility to mines and mine-like objects

HF1, HF8, MF1, MF5

HRC

HRC SOCAL

SOCAL

Surface Warfare

Explosive

Gun Testing—Large-Caliber

Surface crews defend against surface targets with large-caliber guns

HRC

HRC-SOCAL

SOCAL

504

Explosive

Gun Testing—Medium-Caliber

Surface crews defend against surface targets with medium-caliber guns

HRC

HRC-SOCAL

SOCAL

336

Explosive

Missile and Rocket Testing

Missile and rocket testing includes various missiles or rockets fired from submarines and surface combatants. Testing of the launching system and ship defense is performed

HRC

HRC-SOCAL

SOCAL

168

140

Unmanned Systems

Acoustic

Unmanned Surface Vehicle System Testing

Testing involves the production or upgrade of unmanned surface vehicles. This may include tests of mine detection capabilities, evaluations of the basic functions of individual platforms, or complex events with multiple vehicles

HF4, SAS2

HRC

SOCAL

Acoustic

Unmanned Underwater Vehicle Testing

Testing involves the production or upgrade of unmanned underwater vehicles. This may include tests of mine detection capabilities, evaluations of the basic functions of individual platforms, or complex events with multiple vehicles

HF4, MF9

HRC

SOCAL

2,037

Vessel Evaluation

Acoustic

Submarine Sea Trials-Weapons System Testing

Submarine weapons and sonar systems are tested at-sea to meet the integrated combat system certification requirements

HF1, M3, MF3, MF9, MF10, TORP2

HRC

SOCAL

Explosive

Surface Warfare Testing

Tests the capabilities of shipboard sensors to detect, track, and engage surface targets. Testing may include ships defending against surface targets using explosive and non-explosive rounds, gun system structural test firing, and demonstration of the response to Call for Fire against land-based targets (simulated by sea-based locations)

E1, E5, E8

HRC

HRC-SOCAL

SOCAL

441

102

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

ASW4, HF4, HF8, MF1, MF4, MF5, MF6, TORP1, TORP2

HRC

HRC SOCAL

SOCAL

Acoustic

Vessel Signature Evaluation

Surface ship, submarine and auxiliary system signature assessments. This may include electronic, radar, acoustic, infrared and magnetic signatures

ASW3

HRC

HRC SOCAL

SOCAL

252

168

Other Testing Activities

Acoustic

Insertion/Extraction

Testing of submersibles capable of inserting and extracting personnel and payloads into denied areas from strategic distances

M3, MF9

HRC

SOCAL

Acoustic

Signature Analysis Operations

Surface ship and submarine testing of electromagnetic, acoustic, optical, and radar signature measurements

HF1, M3, MF9

HRC

SOCAL

Notes:

HRC = Hawaii Range Complex, SOCAL = Southern California Range Complex, HSTT = Hawaii-Southern California Training and Testing, CA = California, HI = Hawaii.

Office of Naval Research

The proposed Office of Naval Research testing activities that could occur over the seven-year period within the HSTT Study Area are presented in Table 4.

Table 4—Proposed Office of Naval Research Testing Activities Analyzed for Seven-Year Period in the HSTT Study Area

Stressor category

Activity name

Description

Source bin

Location

7-Year

number of events

Acoustic and Oceanographic Science and Technology

Explosive, Acoustic

Acoustic and Oceanographic Research

Research using active transmissions from sources deployed from ships and unmanned underwater vehicles. Research sources can be used as proxies for current and future Navy systems

AG, ASW2, BB4, BB9, LF3, LF4, LF5, MF8, MF9, MF9, MF9, E3

HRC

SOCAL

Acoustic

Long Range Acoustic Communications

Bottom mounted acoustic source off of the Hawaiian Island of Kauai will transmit a variety of acoustic communications sequences

LF4

HRC

Notes:

HRC = Hawaii Range Complex, SOCAL = Southern California Range Complex.

Naval Information Warfare Systems Command

The proposed Naval Information Warfare Systems Command testing activities that could occur over the seven-year period within the HSTT Study Area are presented in Table 5.

Table 5—Proposed Naval Information Warfare Systems Command Testing Activities Analyzed for Seven-Year Period in the HSTT Study Area

Stressor category

Activity name

Description

Source bin

Location

7-Year

number of events

Acoustic

Anti-Terrorism/Force Protection

Testing sensor systems that can detect threats to naval piers, ships, and shore infrastructure

SD1

San Diego, CA

SOCAL

112

Acoustic

Communications

Testing of underwater communications and networks to extend the principles of FORCEnet below the ocean surface

ASW2, ASW5, HF6, LF4

HRC

SOCAL

Acoustic

Energy and Intelligence, Surveillance, and Reconnaissance Sensor Systems

Develop, integrate, and demonstrate Intelligence, Surveillance, and Reconnaissance systems and in-situ energy systems to support deployed systems

AG, HF2, HF7, LF4, LF5, LF6, MF10

HRC

SOCAL

HSTT Transit Corridor

357

Acoustic

Vehicle Testing

Testing of surface and subsurface vehicles and sensor systems that may involve Unmanned Underwater Vehicles, gliders, and Unmanned Surface Vehicles

BB4, FLS2, FLS3, HF6, LF3, M3, MF9, MF13, SAS1, SAS2, SAS3

HRC

SOCAL

HSTT Transit Corridor

1,141

Notes:

HRC = Hawaii Range Complex, SOCAL = Southern California Range Complex, HSTT = Hawaii-Southern California Training and Testing, CA = California.

Summary of Acoustic and Explosive Sources Analyzed for Training and Testing

Tables 6 through 9 show the acoustic and explosive source classes, bins, and numbers used, airgun sources and numbers used, and numbers of pile driving and removal activities associated with the Navy's proposed training and testing activities over a seven-year period in the HSTT Study Area that were analyzed in the 2019 Navy application and for this proposed rule. The annual numbers for acoustic source classes, explosive source bins, and airgun sources, as well as the annual pile driving and removal activities associated with Navy training and testing activities in the HSTT Study Area are identical to those presented in Tables 9 through 12 of the 2018 HSTT final rule, and are not repeated here. Consistent with the periodicity in the 2018 HSTT final rule, the Navy proposes the addition of two pile driving/extraction activities for each of the two additional years.

Table 6 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 proposed training and testing activities. Acoustic source bin use in the proposed activities would vary annually. The seven-year totals for the proposed training and testing activities take into account that annual variability.

Table 6—Acoustic Source Classes Analyzed and Number Used for Seven-Year Period for Training and Testing Activities in the HSTT Study Area

Source class category

Bin

Description

Unit

Training

7-year total

Testing

7-year total

Low-Frequency (LF): Sources that produce signals less than 1 kHz

LF3

LF4

LF sources greater than 200 dB

LF sources equal to 180 dB and up to 200 dB

1,365

4,496

140

LF5

LF sources less than 180 dB

14,458

LF6

LF sources greater than 200 dB with long pulse lengths

956

360

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-61)

38,489

8,692

MF1K

Kingfisher mode associated with MF1 sonars

700

MF2

Hull-mounted surface ship sonars (

e.g.,

AN/SQS-56)

378

MF3

Hull-mounted submarine sonars (

e.g.,

AN/BQQ-10)

14,700

9,177

MF4

Helicopter-deployed dipping sonars (

e.g.,

AN/AQS-22 and AN/AQS-13)

2,719

2,502

MF5

Active acoustic sonobuoys (

e.g.,

DICASS)

40,128

38,233

MF6

Active underwater sound signal devices (

e.g.,

MK 84)

8,202

MF8

Active sources (greater than 200 dB) not otherwise binned

490

MF9

Active sources (equal to 180 dB and up to 200 dB) not otherwise binned

36,056

MF10

Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned

13,104

MF11

Hull-mounted surface ship sonars with an active duty cycle greater than 80%

5,205

392

MF12

Towed array surface ship sonars with an active duty cycle greater than 80%

1,260

4,620

MF13

MF sonar source

2,100

High-Frequency (HF): Tactical and non-tactical sources that produce signals between 10 and 100 kHz

HF1

HF2

Hull-mounted submarine sonars (

e.g.,

AN/BQQ-10)

HF Marine Mammal Monitoring System

12,550

5,403

840

HF3

Other hull-mounted submarine sonars (classified)

1,919

769

HF4

Mine detection, classification, and neutralization sonar (

e.g.,

AN/SQS-20)

15,012

114,069

HF5

Active sources (greater than 200 dB) not otherwise binned

6,720

280

HF6

Active sources (equal to 180 dB and up to 200 dB) not otherwise binned

7,015

HF7

Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned

9,660

HF8

Hull-mounted surface ship sonars (

e.g.,

AN/SQS-61)

711

5,136

Anti-Submarine Warfare (ASW): Tactical sources (

e.g.,

active sonobuoys and acoustic countermeasures systems) used during ASW training and testing activities

ASW1

ASW2

ASW3

MF systems operating above 200 dB

MF Multistatic Active Coherent sonobuoy (

e.g.,

AN/SSQ-125)

MF towed active acoustic countermeasure systems (

e.g.,

AN/SLQ-25)

1,503

4,824

37,385

3,290

32,900

19,187

ASW4

MF expendable active acoustic device countermeasures (

e.g..,

MK 3)

9,023

15,398

ASW5

MF sonobuoys with high duty cycles

1,780

3,854

Torpedoes (TORP): Source classes associated with the active acoustic signals produced by torpedoes

TORP1

TORP2

TORP3

Lightweight torpedo (

e.g.,

MK 46, MK 54, or Anti-Torpedo Torpedo)

Heavyweight torpedo (

e.g.,

MK 48)

1,605

3,515

6,454

2,756

315

Forward Looking Sonar (FLS): Forward or upward looking object avoidance sonars used for ship navigation and safety

FLS2

FLS3

HF sources with short pulse lengths, narrow beam widths, and focused beam patterns

VHF sources with short pulse lengths, narrow beam widths, and focused beam patterns

196

3,424

18,480

Acoustic Modems (M): Systems used to transmit data through the water

MF acoustic modems (greater than 190 dB)

274

3,623

Swimmer Detection Sonars (SD): Systems used to detect divers and submerged swimmers

SD1-SD2

HF and VHF sources with short pulse lengths, used for the detection of swimmers and other objects for the purpose of port security

Synthetic Aperture Sonars (SAS): Sonars in which active acoustic signals are post-processed to form high-resolution images of the seafloor

SAS1

SAS2

SAS3

SAS4

MF SAS systems

HF SAS systems

VHF SAS systems

MF to HF broadband mine countermeasure sonar

6,297

294

13,720

60,088

32,200

Broadband Sound Sources (BB): Sonar systems with large frequency spectra, used for various purposes

BB4

BB7

BB9

LF to MF oceanographic source

LF oceanographic source

MF optoacoustic source

6,414

196

3,360

H = hours; C = count (

e.g.,

number of individual pings or individual sonobuoys).

MF2/MF2K are sources on frigate class ships, which were decommissioned during Phase II.

Formerly ASW2 (H) in Phase II.

Notes: dB = decibel(s), kHz = kilohertz, VHF = very high frequency.

Table 7 describes the number of air gun shots that could occur over seven years under the proposed training and testing activities.

Table 7—Training and Testing Air Gun Sources Quantitatively Analyzed in the HSTT Study Area

Source class category

Bin

Unit

Training

7-year total

Testing

7-year total

Air Guns (AG): small underwater air guns

5,908

C = count. One count (C) of AG is equivalent to 100 air gun firings.

Table 8 summarizes the impact pile driving and vibratory pile removal activities that would occur during a 24-hour period. Annually, for impact pile driving, the Navy will drive 119 piles, two times a year for a total of 238 piles. Over the seven-year period of the rule, the Navy will drive a total of 1,666 piles by impact pile driving. Annually, for vibratory pile extraction, the Navy will extract 119 piles, two times a year for a total of 238 piles. Over the seven-year period of the rule, the Navy will extract a total of 1,666 piles by vibratory pile extraction.

Table 8—Summary of Pile Driving and Removal Activities per 24-Hour Period in the HSTT Study Area

Method

Piles per 24-hour period

Time per pile

(minutes)

Total estimated time of noise per 24-hour period

(minutes)

Pile Driving (Impact)

Pile Removal (Vibratory)

Table 9 describes the number of in-water explosives that could be used in any year under the proposed training and testing activities. Under the proposed activities bin use would vary annually, and the seven-year totals for the proposed training and testing activities take into account that annual variability.

Table 9—Explosive Source Bins Analyzed and Number Used for Seven-Year Period for Training and Testing Activities Within the HSTT Study Area

Bin

Net explosive weight

(lb.)

Example explosive source

Modeled

underwater detonation depths

(ft.)

Training

7-year total

Testing

7-year total

0.1-0.25

Medium-caliber projectiles

0.3, 60

20,580

87,012

>0.25-0.5

Medium-caliber projectiles

0.3, 50

12,222

>0.5-2.5

Large-caliber projectiles

0.3, 60

19,579

20,848

>2.5-5

Mine neutralization charge

10, 16, 33, 50, 61, 65, 650

266

4,372

>5-10

5 in. projectiles

0.3, 10, 50

33,310

9,800

>10-20

Hellfire missile

0.3, 10, 50, 60

4,056

230

>20-60

Demo block/shaped charge

10, 50, 60

>60-100

Lightweight torpedo

0.3, 150

241

399

>100-250

500 lb. bomb

0.3

2,950

E10

>250-500

Harpoon missile

0.3

1,543

210

E11

>500-650

650 lb. mine

61, 150

E12

>650-1,000

2,000 lb. bomb

0.3

114

E13

>1,000-1,740

Multiple Mat Weave charges

Net Explosive Weight refers to the amount of explosives; the actual weight of a munition may be larger due to other components.

Not modeled because charge is detonated in surf zone; not a single E13 charge, but multiple smaller charges detonated in quick succession.

Notes:

in. = inch(es), lb. = pound(s), ft. = feet.

Vessel Movement

Vessels used as part of the Planned Activities include ships, submarines, unmanned vessels, and boats ranging in size from small, 22 ft (7 m) rigid hull inflatable boats to aircraft carriers with lengths up to 1,092 ft (333 m). The average speed of large Navy ships ranges between 10 and 15 knots and submarines generally operate at speeds in the range of 8-13 knots (kn), while a few specialized vessels can travel at faster speeds. Small craft (for purposes of this analysis, less than 18 m in length) have much more variable speeds (0-50+ kn, dependent on the activity), but generally range from 10 to 14 kn. From unpublished Navy data, average median speed for large Navy ships in the HSTT Study Area from 2011-2015 varied from 5-10 kn with variations by ship class and location (

i.e.,

slower speeds close to the coast). While these speeds for large and small craft are representative of most events, some vessels need to temporarily operate outside of these parameters. A full description of Navy vessels that are used during training and testing activities can be found in the 2017 Navy

application and Chapter 2 (

Description of Proposed Action and Alternatives

) of the 2018 HSTT FEIS/OEIS.

The number of Navy vessels used in the HSTT Study Area varies based on military training and testing requirements, deployment schedules, annual budgets, and other dynamic factors. Most training and testing activities involve the use of vessels. These activities could be widely dispersed throughout the HSTT Study Area, but would typically be conducted near naval ports, piers, and range areas. Navy vessel traffic would be especially concentrated near San Diego, California and Pearl Harbor, Hawaii. There is no seasonal differentiation in Navy vessel use because of continual operational requirements from Combatant Commanders. The majority of large vessel traffic occurs between the installations and the OPAREAs. Support craft would be more concentrated in the coastal waters in the areas of naval installations, ports, and ranges. Activities involving vessel movements occur intermittently and are variable in duration, ranging from a few hours up to weeks.

The Navy proposes no changes to the manner in which Navy vessels would be used during training and testing activities, the speeds at which they operate, the number of vessels that would be used during various activities, or the locations in which Navy vessel movement would be concentrated within the HSTT Study Area from those analyzed in the 2018 HSTT final rule. The only change related to the Navy's request regarding Navy vessel movement is the vessel use associated with the additional two years of Navy activities.

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 a real-world situation 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 proposed activities and included them in the environmental analysis. Details on standard operating procedures were provided in the 2018 HSTT proposed rule; please see the 2018 HSTT proposed rule, the 2017 Navy application, and Chapter 2 (

Description of Proposed Action and Alternatives

) of the 2018 HSTT FEIS/OEIS for more information. The Navy proposes no changes to the Standard Operating Procedures from those included in the 2018 HSTT final rule.

Description of Marine Mammals and Their Habitat in the Area of the Specified Activities

Marine mammal species and their associated stocks that have the potential to occur in the HSTT Study Area are presented in Table 10 along with the best/minimum abundance estimate and associated coefficient of variation value. Consistent with the 2018 HSTT final rule, the Navy still anticipates the take of individuals from 38 marine mammal species by Level A harassment and Level B harassment incidental to training and testing activities from the use of sonar and other transducers, in-water detonations, air guns, and impact pile driving/vibratory extraction activities. The Navy requested authorization for 13 serious injuries or mortalities combined of two marine mammal stocks from explosives, and three takes of large whales by serious injury or mortality from vessel strikes over the seven-year period. Two marine mammal species, the Hawaiian monk seal and the Main Hawaiian Islands Insular Distinct Population Segment (DPS) of false killer whale, have critical habitat designated under the Endangered Species Act (ESA) in the HSTT Study Area.

We presented a detailed discussion of marine mammals and their occurrence in the HSTT Study Area, inclusive of important marine mammal habitat (

e.g.,

ESA-designated critical habitat), biologically important areas (BIAs), national marine sanctuaries (NMSs), and unusual mortality events (UMEs) in the 2018 HSTT proposed rule and 2018 HSTT final rule; please see these rules and the 2017 and 2019 Navy applications for additional information. There have been no changes to important marine mammal habitat, BIAs, NMSs, or ESA designated critical habitat since the issuance of the 2018 HSTT final rule; therefore the information that supports our determinations here can be found in the 2018 HSTT proposed and final rules. NMFS has reviewed the most recent 2018 final Stock Assessment Reports (SARs); information on relevant UMEs; and other scientific literature, and determined that none of these nor any other new information changes our determination of which species or stocks have the potential to be affected by the Navy's activities or the pertinent information in the

Description of Marine Mammals and Their Habitat in the Area of the Specified Activities

section in the 2018 HSTT proposed and final rules. Therefore the information presented in those sections of the 2018 HSTT proposed and final rules remains current and valid.

The species considered but not carried forward for analysis are two American Samoa stocks of spinner dolphins—(1) the Kure and Midway stock and (2) the Pearl and Hermes stock. There is no potential for overlap with any stressors from Navy activities and therefore there would be no incidental takes, in which case, these stocks are not considered further.

Table 10—Marine Mammal Occurrence Within the HSTT Study Area

Common name

Scientific name

Stock

Status

MMPA

ESA

Occurrence

Seasonal absence

Stock

abundance

(CV)/minimum

population

Blue whale

Balaenoptera musculus

Eastern North Pacific

Strategic, Depleted

Endangered

Southern California

1,647 (0.07)/1,551.

Central North Pacific

Strategic, Depleted

Endangered

Hawaii

Summer

133 (1.09)/63.

Bryde's whale

Balaenoptera brydei/edeni

Eastern Tropical Pacific

Southern California

unknown.

Hawaii

1,751 (0.29)/1,378.

Fin whale

Balaenoptera physalus

CA/OR/WA

Strategic, Depleted

Endangered

Southern California

9,029 (0.12)/8,127.

Hawaii

Strategic, Depleted

Endangered

Hawaii

Summer

154 (1.05)/75.

Gray whale

Eschrichtius robustus

Eastern North Pacific

Southern California

26,960 (0.05)/25,849.

Western North Pacific

Strategic, Depleted

Endangered

Southern California

290 (NA)/271.

Humpback whale

Megaptera novaeangliae

CA/OR/WA

Strategic, Depleted

Threatened/ Endangered

Southern California

2,900 (0.05)/2,784.

Central North Pacific

Strategic

Hawaii

Summer

10,103 (0.30)/7,891.

Minke whale

Balaenoptera acutorostrata

CA/OR/WA

Southern California

636 (0.72)/369.

Hawaii

Summer

unknown.

Sei whale

Balaenoptera borealis

Eastern North Pacific

Strategic, Depleted

Endangered

Southern California

519 (0.40)/374.

Hawaii

Strategic, Depleted

Endangered

Hawaii

Summer

391 (0.90)/204.

Sperm whale

Physeter macrocephalus

CA/OR/WA

Strategic, Depleted

Endangered

Southern California

1,997 (0.57)/1,270.

Hawaii

Strategic, Depleted

Endangered

Hawaii

4,559 (0.33)/3,478.

Pygmy sperm whale

Kogia breviceps

CA/OR/WA

Southern California

Winter and Fall

4,111 (1.12)/1,924.

Hawaii

unknown.

Dwarf sperm whale

Kogia sima

CA/OR/WA

Southern California

unknown.

Hawaii

unknown.

Baird's beaked whale

Berardius bairdii

CA/OR/WA

Southern California

2,697 (0.60)/1,633.

Blainville's beaked whale

Mesoplodon densirostris

Hawaii

2,105 (1.13)/980.

Cuvier's beaked whale

Ziphius cavirostris

CA/OR/WA

Southern California

3,274 (0.67)/2,059.

Hawaii

723 0.69/428.

Longman's beaked whale

Indopacetus pacificus

Hawaii

7,619 (0.66)/4,592.

Mesoplodon beaked whales

Mesoplodon spp.

CA/OR/WA

Southern California

3,044 (0.54)/1,967.

Common Bottlenose dolphin

Tursiops truncatus

California Coastal

Southern California

453 (0.06)/346.

CA/OR/WA Offshore

Southern California

1,924 (0.54)/1,255.

Hawaii Pelagic

Hawaii

21,815 (0.57)/13,957.

Kauai and Niihau

Hawaii

NA NA/97.

Oahu

Hawaii

NA.

4-Islands

Hawaii

NA.

Hawaii Island

Hawaii

NA NA/91.

False killer whale

Pseudorca crassidens

Main Hawaiian Islands Insular

Strategic, Depleted

Endangered

Hawaii

167 (0.14)/149.

Hawaii Pelagic

Hawaii

1,540 (0.66)/928.

Northwestern Hawaiian Islands

Hawaii

617 (1.11)/290.

Fraser's dolphin

Lagenodelphis hosei

Hawaii

51,491 (0.66)/31,034.

Killer whale

Orcinus orca

Eastern North Pacific Offshore

Southern California

300 (0.1)/276.

Eastern North Pacific Transient/West Coast Transient

Southern California

243 unknown/243.

Hawaii

146 (0.96)/74.

Long-beaked common dolphin

Delphinus capensis

California

Southern California

101,305 (0.49)/68,432.

Melon-headed whale

Peponocephala electra

Hawaiian Islands

Hawaii

8,666 (1.00)/4,299.

Kohala Resident

Hawaii

447 (0.12)/404.

Northern right whale dolphin

Lissodelphis borealis

CA/OR/WA

Southern California

26,556 (0.44)/18,608.

Pacific white-sided dolphin

Lagenorhynchus obliquidens

CA/OR/WA

Southern California

26,814 (0.28)/21,195.

Pantropical spotted dolphin

Stenella attenuata

Oahu

Hawaii

unknown.

4-Islands

Hawaii

unknown.

Hawaii Island

Hawaii

unknown.

Hawaii Pelagic

Hawaii

55,795 (0.40)/40,338.

Pygmy killer whale

Feresa attenuata

Tropical

Southern California

Winter & Spring

unknown.

Hawaii

10,640 (0.53)/6,998.

Risso's dolphins

Grampus griseus

CA/OR/WA

Southern California

6,336 (0.32)/4,817.

Hawaii

11,613 (0.43)/8,210.

Rough-toothed dolphin

Steno bredanensis

NSD

Southern California

unknown.

Hawaii

72,528 (0.39)/52,833.

Short-beaked common dolphin

Delphinus delphis

CA/OR/WA

Southern California

969,861 (0.17)/839,325.

Short-finned pilot whale

Globicephala macrorhynchus

CA/OR/WA

Southern California

836 (0.79)/466.

Hawaii

19,503 (0.49)/13,197.

Spinner dolphin

Stenella longirostris

Hawaii Pelagic

Hawaii

unknown.

Hawaii Island

Hawaii

665 (0.09)/617.

Oahu and 4-Islands

Hawaii

NA.

Kauai and Niihau

Hawaii

NA.

Kure and Midway

Hawaii

unknown.

Pearl and Hermes

Hawaii

unknown.

Striped dolphin

Stenella coeruleoalba

CA/OR/WA

Southern California

29,211 (0.20)/24,782.

Hawaii

61,021 (0.38)/44,922.

Dall's porpoise

Phocoenoides dalli

CA/OR/WA

Southern California

25,750 (0.45)/17,954

Harbor seal

Phoca vitulina

California

Southern California

30,968 (NA)/27,348.

Hawaiian monk seal

Neomonachus schauinslandi

Hawaii

Strategic, Depleted

Endangered

Hawaii

1,415 (0.03)/1,384.

Northern elephant seal

Mirounga angustirostris

California

Southern California

179,000 (NA)/81,368.

California sea lion

Zalophus californianus

U.S. Stock

Southern California

257,606 (NA)/233,515.

Guadalupe fur seal

Arctocephalus townsendi

Mexico to California

Strategic, Depleted

Threatened

Southern California

20,000 (NA)/15,830.

Northern fur seal

Callorhinus ursinus

California

Southern California

14,050 (NA)/7,524.

The two humpback whale Distinct Population Segments (DPSs) making up the California, Oregon, and Washington (CA/OR/WA) stock present in Southern California are the Mexico DPS, listed under the ESA as Threatened, and the Central America DPS, which is listed under the ESA as Endangered.

This stock is mentioned briefly in the Pacific Stock Assessment Report (Carretta

et al.,

2017) and referred to as the “Eastern North Pacific Transient” stock; however, the Alaska Stock Assessment Report contains assessments of all transient killer whale stocks in the Pacific and the Alaska Stock Assessment Report refers to this same stock as the “West Coast Transient” stock (Muto

et al.,

2017).

NSD—No stock designation. Rough-toothed dolphin has a range known to include the waters off Southern California, but there is no recognized stock or data available for the U.S West Coast.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

We provided a full discussion of the potential effects of the specified activities on marine mammals and their habitat in our 2018 HSTT proposed rule and 2018 HSTT final rule. In the

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

section of the 2018 HSTT proposed and final rules, NMFS provided a description of the ways marine mammals may be affected by the same activities that the Navy will be conducting during the seven-year period analyzed in this rule in the form of serious injury or mortality, physical trauma, sensory impairment (permanent and temporary threshold shifts and acoustic masking), physiological responses (particularly stress responses), behavioral disturbance, or habitat effects. Therefore, we do not repeat the information here, all of which remains current and applicable, but refer the reader to those rules and the 2018 HSTT FEIS/OEIS (Chapter 3, Section 3.7

Marine Mammals

), which NMFS participated in the development of via our cooperating agency status and adopted to meet our NEPA requirements.

In addition, NMFS has reviewed new information in relevant SARs, any new information on active UMEs or new UMEs, and new scientific literature. Summaries of current UMEs and new scientific literature since publication of the 2018 HSTT final rule are presented below.

Unusual Mortality Events (UME)

An UME is defined under Section 410(6) of the MMPA as a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response. From 1991 to the present, there have been 17 formally recognized UMEs affecting marine mammals in California and Hawaii and involving species under NMFS' jurisdiction. Three UMEs that could be relevant to informing the current analysis are discussed below. Specifically, the California sea lion UME in California is still open, but will be closed soon. The Guadalupe fur seal UME in California and the gray whale UME along the west coast of North America are active and involve ongoing investigations.

California Sea Lion UME

From January 2013 through September 2016, a greater than expected number of young malnourished California sea lions (

Zalophus californianus

) stranded along the coast of California. Sea lions stranding from an early age (6-8 months old) through two years of age (hereafter referred to as juveniles) were consistently underweight without other disease processes detected. Of the 8,122 stranded juveniles attributed to the UME, 93 percent stranded alive (n=7,587, with 3,418 of these released after rehabilitation) and 7 percent (n=531) stranded dead. Several factors are hypothesized to have impacted the ability of nursing females and young sea lions to acquire adequate nutrition for successful pup rearing and juvenile growth. In late 2012, decreased anchovy and sardine recruitment (CalCOFI data, July 2013) may have led to nutritionally stressed adult females. Biotoxins were present at various times throughout the UME, and while they were not detected in the stranded juvenile sea lions (whose stomachs were empty at the time of stranding), biotoxins may have impacted the adult females' ability to support their dependent pups by affecting their cognitive function (

e.g.

navigation, behavior towards their offspring). Therefore, the role of biotoxins in this UME, via its possible impact on adult females' ability to support their pups, is unclear. The proposed primary cause of the UME was malnutrition of sea lion pups and yearlings due to ecological factors. These factors included shifts in distribution, abundance and/or quality of sea lion prey items around the Channel Island rookeries during critical sea lion life history events (nursing by adult females, and transitioning from milk to prey by young sea lions). These prey shifts were most likely driven by unusual oceanographic conditions at the time due to the “Warm Water Blob” and El Niño. This investigation will soon be closed. Please refer to:

https://www.fisheries.noaa.gov/national/marine-life-distress/2013-2017-california-sea-lion-unusual-mortality-event-california

for more information on this UME.

Guadalupe Fur Seal UME

Increased strandings of Guadalupe fur seals began along the entire coast of California in January 2015 and were eight times higher than the historical average (approximately 10 seals/yr). Strandings have continued since 2015 and have remained well above average through 2017. Strandings have continued since 2015 and remained well above average through 2019. Numbers by year are as follows: 2015 (98), 2016 (76), 2017 (61), 2018 (45), 2019 (104, as of June 28, 2019). The total number of Guadalupe fur seals from January 1, 2015, through June 28, 2019, in the UME is 438. Additionally, strandings of Guadalupe fur seals became elevated in the spring of 2019 in Washington and Oregon, subsequently strandings for seals in these two states have been added to the UME starting from January 1, 2019. The current total number of strandings for 2019 in Washington and Oregon is 55 seals as of June 28, 2019. Strandings are seasonal and generally peak in April through June of each year. The Guadalupe fur seal strandings have been mostly weaned pups and juveniles (1-2 years old) with both live and dead strandings occurring. Current findings from the majority of stranded animals include primary malnutrition with secondary bacterial and parasitic infections. This California portion of this UME is occurring in the same area as the 2013-2016 California sea lion UME. This investigation is ongoing. Please refer to:

https://www.fisheries.noaa.gov/national/marine-life-distress/2015-2019-guadalupe-fur-seal-unusual-mortality-event-california

for more information on this UME.

Gray Whale UME

Since January 1, 2019, elevated gray whale strandings have occurred along the west coast of North America, from Mexico to Canada. As of June 28, 2019, there have been a total of 170 strandings along the coasts of the U.S., Canada, and Mexico, with 84 of those strandings occurring along the U.S. coast. Partial necropsy examinations conducted on a subset of stranded whales have shown evidence of emaciation. As part of the UME investigation process, NOAA is assembling an independent team of scientists to coordinate with the Working Group on Marine Mammal Unusual Mortality Events to review the data collected, sample stranded whales, and determine the next steps for the investigation. Please refer to:

https://www.fisheries.noaa.gov/national/marine-life-distress/2019-gray-whale-unusual-mortality-event-along-west-coast

for more information on this UME.

New Pertinent Science Since Publication of the 2018 HSTT Final Rule

Southall

et al.

(2019a) evaluated Southall

et al.

(2007) and used updated scientific information to propose revised noise exposure criteria to predict onset of auditory effects in marine mammals (

i.e.,

PTS and TTS onset). Southall

et al.

(2019a) note that the quantitative processes described and the resulting exposure criteria (

i.e.,

thresholds and auditory weighting functions) are largely identical to those in Finneran (2016) and NMFS (2016 and 2018).

However they differ in that the Southall

et al.

(2019a) exposure criteria are more broadly applicable as they include all marine mammal species (rather than only those under NMFS jurisdiction) for all noise exposures (both in air and underwater for amphibious species) and, while the hearing group compositions are identical, they renamed the hearing groups.

Recent studies on the behavioral responses of cetaceans to sonar examine and continue to demonstrate the importance of not only sound source parameters, but exposure context (

e.g.,

behavioral state, presence of other animals and social relationships, prey abundance, distance to source, presence of vessels, environmental parameters, etc.) in determining or predicting a behavioral response. Kastelein

et al.

(2018) examined the role of sound pressure level (SPL) and duty cycle on the behavior of two captive harbor porpoises when exposed to simulated Navy mid-frequency sonar (53C, 3.5 to 4.1 kHz). Neither harbor porpoise responded to the low duty cycle (2.7 percent) at any of the five SPLs presented, even at the maximum received SPL (143 dB re: 1 µPa). At the higher duty cycle (96 percent), one porpoise responded by increasing his respiration rate at a received SPL of greater than or equal to 119 dB re: 1 µPa, and moved away from the transducer at a received SPL of 143 dB re: 1 µPa. Kastelein

et al.

(2018) observed that at the same received SPL and duty cycle, harbor porpoises respond less to 53C sonar sounds than 1-2 kHz, 6-7 kHz, and 25 kHz sonar signals observed in previous studies, but noted that when examining behavioral responses it is important to take into account the spectrum and temporal structure of the signal, the duty cycle, and the psychological interpretation by the animal. Wensveen

et al.

(2019) examined the role of sound source (simulated sonar pulses) distance and received level in northern bottlenose whales in an environment without frequent sonar activity using multi-scaled controlled exposure experiments. They observed behavioral avoidance of the sound source over a wide range of distances (0.8-28 km) and estimated avoidance thresholds ranging from received SPLs of 117-126 dB re: 1 µPa. The behavioral response characteristics and avoidance thresholds were comparable to those previously observed in beaked whale studies; however, they did not observe an effect of distance on behavioral response and found that onset and intensity of behavioral response were better predicted by received SPL. When conducting controlled exposure experiments on blue whales Southall

et al.

(2019b) observed that after exposure to simulated and operational mid-frequency active sonar, more than 50 percent of blue whales in deep-diving states responded to the sonar, while no behavioral response was observed in shallow-feeding blue whales. The behavioral responses they observed were generally brief, of low to moderate severity, and highly dependent on exposure context (behavioral state, source-to-whale horizontal range, and prey availability). Blue whale response did not follow a simple exposure-response model based on received sound exposure level. In a review of the potential impacts of sonar on beaked whales, Bernaldo de Quirós

et al.

(2019) suggested that the effect of mid-frequency active sonar on beaked whales varies among individuals or populations, and that predisposing conditions such as previous exposure to sonar and individual health risk factors may contribute to individual outcomes (such as decompression sickness).

Having considered this information, we have preliminarily determined that there is no new information that substantively affects our analysis of impacts on marine mammals and their habitat that appeared in the 2018 HSTT final rule, all of which remains applicable and valid for our assessment of the effects of the Navy's activities during the seven-year period of this rule.

Estimated Take of Marine Mammals

This section indicates the number of takes that NMFS is proposing to authorize, which are based on the amount of take that NMFS anticipates could occur or is likely to occur, depending on the type of take and the methods used to estimate it, as described below. NMFS coordinated closely with the Navy in the development of their incidental take application, and preliminarily agrees that the methods the Navy has put forth described herein and in the 2018 HSTT proposed and final rules to estimate take (including the model, thresholds, and density estimates), and the resulting numbers are based on the best available science and appropriate for authorization. The number and type of incidental takes that could occur or are likely to occur annually remain identical to those authorized in the 2018 HSTT regulations.

Takes are predominantly in the form of harassment, but a small number of serious injuries or mortalities are also possible. For military readiness activities, the MMPA defines “harassment” as (i) Any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) Any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered (Level B harassment).

Proposed authorized takes would primarily be in the form of Level B harassment, as use of the acoustic and explosive sources (

i.e.,

sonar, air guns, pile driving, explosives) is more likely to result in behavioral disruption (rising to the level of a take as described above) or temporary threshold shift (TTS) for marine mammals than other forms of take. There is also the potential for Level A harassment, however, in the form of auditory injury and/or tissue damage (the latter from explosives only) to result from exposure to the sound sources utilized in training and testing activities. Lastly, no more than three serious injuries or mortalities total (over the seven-year period) of mysticetes (except for sei whales, minke whales, Bryde's whales, Central North Pacific stock of blue whales, Hawaii stock of fin whales, and Western North Pacific stock of gray whales) and the Hawaii stock of sperm whales have the potential occur through vessel collisions. Although we analyze the impacts of these potential serious injuries or mortalities that are proposed to be authorized, the required mitigation and monitoring measures are expected to minimize the likelihood that ship strike or these high-level explosive exposures (and the associated serious injury or mortality) actually occur.

Generally speaking, for acoustic impacts we estimate the amount and type of harassment by considering: (1) Acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be taken by Level B harassment (in this case, as defined in the military readiness definition of Level B harassment included above) or incur some degree of temporary or permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day or event; (3) the density or occurrence of marine mammals within these ensonified areas; and (4) and the number of days of activities or events.

Acoustic Thresholds

Using the best available science, NMFS, in coordination with the Navy, has established acoustic thresholds that identify the most appropriate received level of underwater sound above which marine mammals exposed to these sound sources could be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered, or to incur TTS (equated to Level B harassment) or permanent threshold shift (PTS) of some degree (equated to Level A harassment). Thresholds have also been developed to identify the pressure levels above which animals may incur non-auditory injury from exposure to pressure waves from explosive detonation.

Despite the quickly evolving science, there are still challenges in quantifying expected behavioral responses that qualify as take by Level B harassment, especially where the goal is to use one or two predictable indicators

(e.g.,

received level and distance) to predict responses that are also driven by additional factors that cannot be easily incorporated into the thresholds (

e.g.,

context). So, while the new behavioral Level B harassment thresholds have been refined here to better consider the best available science (

e.g.,

incorporating both received level and distance), they also still have some built-in conservative factors to address the challenge noted. For example, while duration of observed responses in the data are now considered in the thresholds, some of the responses that are informing take thresholds are of a very short duration, such that it is possible some of these responses might not always rise to the level of disrupting behavior patterns to a point where they are abandoned or significantly altered. We describe the application of this Level B harassment threshold as identifying the maximum number of instances in which marine mammals could be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered. In summary, we believe these behavioral Level B harassment thresholds are the most appropriate method for predicting behavioral Level B harassment given the best available science and the associated uncertainty.

We described these acoustic thresholds and the methods used to determine thresholds, none of which have changed, in detail in the

Acoustic Thresholds

section of the 2018 HSTT final rule; please see the 2018 HSTT final rule for detailed information.

Navy's Acoustic Effects Model

The Navy proposes no changes to the Acoustic Effects Model as described in the 2018 HSTT final rule and there is no new information that would affect the applicability or validity of the model. Please see the 2018 HSTT final and proposed rules and Appendix E of the 2018 HSTT FEIS/OEIS for detailed information.

Range to Effects

The Navy proposes no changes from the 2018 HSTT final rule to the type and nature of the specified activities to be conducted during the seven-year period analyzed in this proposed rule, including equipment and sources used and exercises conducted. There is also no new information that would affect the applicability or validity of the ranges to effects previously analyzed for these activities. Therefore the ranges to effects in this proposed rule are identical to those described and analyzed in the 2018 HSTT final rule, including received sound levels that may cause onset of significant behavioral response and TTS and PTS in hearing for each source type or explosives that may cause non-auditory injury. Please see the

Range to Effects

section and Tables 24 through 40 of the 2018 HSTT final rule for detailed information.

Marine Mammal Density

The Navy proposes no changes to the methods used to estimate marine mammal density described in the 2018 HSTT final rule and there is no new information that would affect the applicability or validity of these methods. Please see the 2018 HSTT final rule for detailed information.

Take Requests

As in the 2018 HSTT final rule, in its 2019 application, the Navy determined that the three stressors below could result in the incidental taking of marine mammals. NMFS has reviewed the Navy's data and analysis and determined that it is complete and accurate, and NMFS agrees that the following stressors have the potential to result in takes of marine mammals from the Navy's planned activities:

• Acoustics (sonar and other transducers; air guns; pile driving/extraction);

• Explosives (explosive shock wave and sound, assumed to encompass the risk due to fragmentation); and

• Physical Disturbance and Strike (vessel strike).

NMFS reviewed and agrees with the Navy's conclusion that acoustic and explosive sources have the potential to result in incidental takes of marine mammals by harassment, serious injury, or mortality. NMFS carefully reviewed the Navy's analysis and conducted its own analysis of vessel strikes, determining that the likelihood of any particular species of large whale being struck is quite low. Nonetheless, NMFS agrees that vessel strikes have the potential to result in incidental take from serious injury or mortality for certain species of large whales and the Navy has specifically requested coverage for these species. Therefore, the likelihood of vessel strikes, and later the effects of the incidental take that is being proposed to be authorized, has been fully analyzed and is described below.

Regarding the quantification of expected takes from acoustic and explosive sources (by Level A and Level B harassment, as well as mortality resulting from exposure to explosives), the number of takes are based directly on the level of activities (days, hours, counts, etc., of different activities and events) in a given year. In the 2018 HSTT final rule, take estimates across the five-years were based on the Navy conducting three years of a representative level of activity and two years of maximum level of activity. Consistent with the pattern set forth in the 2017 Navy application, the 2018 HSTT FEIS/OEIS, and the 2018 HSTT final rule, the Navy proposes to add one additional representative year and one additional maximum year to determine the predicted take numbers in this rule. Specifically, as in the 2018 HSTT final rule, the Navy proposes to use the maximum annual level to calculate annual takes (which would remain identical to what was determined in the 2018 HSTT final rule), and the sum of all years (four representative and three maximum) to calculate the seven-year totals for this rule.

The quantitative analysis process used for the 2018 HSTT FEIS/OEIS and the 2017 and 2019 Navy applications to estimate potential exposures to marine mammals resulting from acoustic and explosive stressors is detailed in 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). The Navy Acoustic Effects Model estimates acoustic and explosive effects without taking mitigation into account; therefore, the model overestimates predicted impacts on marine mammals within mitigation zones. To account for mitigation for marine species in the take estimates, the Navy conducts a quantitative

assessment of mitigation. The Navy conservatively quantifies the manner in which procedural mitigation is expected to reduce the risk for model-estimated PTS for exposures to sonars and for model-estimated mortality for exposures to explosives, based on species sightability, observation area, visibility, and the ability to exercise positive control over the sound source. Where the analysis indicates mitigation would effectively reduce risk, the model-estimated PTS are considered reduced to TTS and the model-estimated mortalities are considered reduced to injury. For a complete explanation of the process for assessing the effects of mitigation, see the 2017 Navy application and the

Take Requests

section of the 2018 HSTT final rule. The extent to which the mitigation areas reduce impacts on the affected species and stocks is addressed separately in the

Preliminary Analysis and Negligible Impact Determination

section.

No changes have been made to the quantitative analysis process to estimate potential exposures to marine mammals resulting from acoustic and explosive stressors and calculate take estimates. In addition, there is no new information that would call into question the validity of the Navy's quantitative analysis process. Please see the documents described in the paragraph above, the 2018 HSTT proposed rule, and the 2018 HSTT final rule for detailed descriptions of these analyses. In summary, we believe the Navy's methods, including the method for incorporating mitigation and avoidance, are the most appropriate methods for predicting PTS, TTS, and behavioral disruption. But even with the consideration of mitigation and avoidance, given some of the more conservative components of the methodology (

e.g.,

the thresholds do not consider ear recovery between pulses), we would describe the application of these methods as identifying the maximum number of instances in which marine mammals would be reasonably expected to be taken through PTS, TTS, or behavioral disruption.

Summary of Requested Take From Training and Testing Activities

Based on the methods discussed in the previous sections and the Navy's model and quantitative assessment of mitigation, the Navy provided its take estimate and request for authorization of takes incidental to the use of acoustic and explosive sources for training and testing activities both annually (based on the maximum number of activities that could occur per 12-month period) and over the seven-year period covered by the 2019 Navy application. Annual takes (based on the maximum number of activities that could occur per 12-month period) from the use of acoustic and explosive sources are identical to those presented in Tables 41 and 42 and in the

Explosives

subsection of the

Take Requests

section of the 2018 HSTT final rule. The 2019 Navy application also includes the Navy's take estimate and request for vessel strikes due to vessel movement in the HSTT Study Area. NMFS has reviewed the Navy's data, methodology, and analysis and determined that it is complete and accurate. NMFS agrees that the estimates for incidental takes by harassment from all sources as well as the incidental takes by serious injury or mortality from explosives requested for authorization are the maximum number of instances in which marine mammals are reasonably expected to be taken. NMFS also agrees that the takes by serious injury or mortality as a result of vessel strikes could occur. Note that the total amount of estimated incidental take from acoustic and explosive sources over the total seven-year period covered by the 2019 Navy application is less than the annual total multiplied by seven because although the annual estimates are based on the maximum number of activities per year and therefore the maximum possible estimated takes, the seven-year total take estimates are based on the sum of three maximum years and four representative years. Not all activities occur every year. Some activities would occur multiple times within a year, and some activities would occur only a few times over the course of the seven-year period. Using seven years of the maximum number of activities each year would vastly overestimate the amount of incidental take that would occur over the seven-year period where the Navy knows that it will not conduct the maximum number of activities each and every year for the seven years.

Estimated Harassment Take From Training Activities

For training activities, Table 11 summarizes the Navy's take estimate and request and the maximum amount and type of Level A harassment and Level B harassment for the seven-year period covered by the 2019 Navy application that NMFS concurs is reasonably expected to occur by species or stock. For the estimated amount and type of Level A harassment and Level B harassment annually, see Table 41 in the 2018 HSTT final rule. Note that take by Level B harassment includes both behavioral disruption and TTS. Navy Figures 6-12 through 6-50 in Section 6 of the 2017 Navy application illustrate the comparative amounts of TTS and behavioral disruption for each species annually, noting that if a modeled marine mammal was “taken” through exposure to both TTS and behavioral disruption in the model, it was recorded as a TTS.

Table 11—Seven-Year Total Species- and Stock-Specific Take Estimates Proposed for Authorization From Acoustic and Explosive Sound Source Effects for All Training Activities

Species

Stock

7-Year total

Level B

Level A

Blue whale *

Central North Pacific

205

Eastern North Pacific

7,116

Bryde's whale †

Eastern Tropical Pacific

167

Hawaiian †

631

Fin whale *

California, Oregon, & Washington

7,731

Hawaiian

197

Humpback whale †

California, Oregon, & Washington †

7,962

Central North Pacific

34,437

Minke whale

California, Oregon, & Washington

4,119

Hawaiian

20,237

Sei whale *

Eastern North Pacific

333

Hawaiian

677

Gray whale †

Eastern North Pacific

16,703

Western North Pacific †

Sperm whale *

California, Oregon, & Washington

8,834

Hawaiian

10,341

Dwarf sperm whale

Hawaiian

84,232

215

Pygmy sperm whale

Hawaiian

33,431

Kogia

whales

California, Oregon, & Washington

38,609

149

Baird's beaked whale

California, Oregon, & Washington

8,524

Blainville's beaked whale

Hawaiian

23,491

Cuvier's beaked whale

California, Oregon, & Washington

47,178

Hawaiian

7,898

Longman's beaked whale

Hawaiian

82,293

Mesoplodon

spp (beaked whale guild)

California, Oregon, & Washington

25,404

Bottlenose dolphin

California Coastal

1,295

California, Oregon, & Washington Offshore

201,619

Hawaiian Pelagic

13,080

Kauai & Niihau

500

Oahu

57,288

4-Island

1,052

Hawaii

291

False killer whale †

Hawaii Pelagic

4,353

Main Hawaiian Islands Insular †

2,710

Northwestern Hawaiian Islands

1,585

Fraser's dolphin

Hawaiian

177,198

Killer whale

Eastern North Pacific Offshore

460

Eastern North Pacific Transient/West Coast Transient

855

Hawaiian

513

Long-beaked common dolphin

California

784,965

Melon-headed whale

Hawaiian Islands

14,137

Kohala Resident

1,278

Northern right whale dolphin

California, Oregon, & Washington

357,001

Pacific white-sided dolphin

California, Oregon, & Washington

274,892

Pantropical spotted dolphin

Hawaii Island

17,739

Hawaii Pelagic

42,318

Oahu

28,860

4-Island

1,816

Pygmy killer whale

Hawaiian

35,531

Tropical

2,977

Risso's dolphin

California, Oregon, & Washington

477,389

Hawaiian

40,800

Rough-toothed dolphin

Hawaiian

26,769

NSD

Short-beaked common dolphin

California, Oregon, & Washington

5,875,431

307

Short-finned pilot whale

California, Oregon, & Washington

6,341

Hawaiian

53,627

Spinner dolphin

Hawaii Island

609

Hawaii Pelagic

18,870

Kauai & Niihau

1,961

Oahu & 4-Island

10,424

Striped dolphin

California, Oregon, & Washington

777,001

Hawaiian

32,806

Dall's porpoise

California, Oregon, & Washington

171,250

894

California sea lion

U.S.

460,145

629

Guadalupe fur seal *

Mexico

3,342

Northern fur seal

California

62,138

Harbor seal

California

19,214

Hawaiian monk seal *

Hawaiian

938

Northern elephant seal

California

241,277

490

* ESA-listed species (all stocks) within the HSTT Study Area.

† Only designated stocks are ESA-listed.

NSD: No stock designation.

Estimated Harassment Take From Testing Activities

For testing activities, Table 12 summarizes the Navy's take estimate and request and the maximum amount and type of Level A harassment and Level B harassment for the seven-year period covered by the 2019 Navy application that NMFS concurs is reasonably expected to occur by species or stock. For the estimated amount and type of Level A harassment and Level B harassment annually, see Table 42 in the 2018 HSTT final rule. Note that take by Level B harassment includes both behavioral disruption and TTS. Navy Figures 6-12 through 6-50 in Section 6 of the 2017 Navy application illustrate

the comparative amounts of TTS and behavioral disruption for each species annually, noting that if a modeled marine mammal was “taken” through exposure to both TTS and behavioral disruption in the model, it was recorded as a TTS.

Table 12—Seven-Year Total Species and Stock-Specific Take Estimates Proposed for Authorization From Acoustic and Explosive Sound Source Effects for All Testing Activities

Species

Stock

7-Year total

Level B

Level A

Blue whale *

Central North Pacific

Eastern North Pacific

5,679

Bryde's whale †

Eastern Tropical Pacific

Hawaiian †

278

Fin whale *

California, Oregon, & Washington

6,662

Hawaiian

108

Humpback whale †

California, Oregon, & Washington †

4,961

Central North Pacific

23,750

Minke whale

California, Oregon, & Washington

1,855

Hawaiian

9,822

Sei whale *

Eastern North Pacific

178

Hawaiian

329

Gray whale †

Eastern North Pacific

13,077

Western North Pacific †

Sperm whale *

California, Oregon, & Washington

7,409

Hawaiian

5,269

Dwarf sperm whale

Hawaiian

43,374

197

Pygmy sperm whale

Hawaiian

17,396

Kogia

whales

California, Oregon, & Washington

20,766

Baird's beaked whale

California, Oregon, & Washington

4,841

Blainville's beaked whale

Hawaiian

11,455

Cuvier's beaked whale

California, Oregon, & Washington

30,180

Hawaiian

3,784

Longman's beaked whale

Hawaiian

41,965

Mesoplodon

spp (beaked whale guild)

California, Oregon, & Washington

16,383

Bottlenose dolphin

California Coastal

11,158

California, Oregon, & Washington Offshore

158,700

Hawaiian Pelagic

8,469

Kauai & Niihau

3,091

Oahu

3,230

4-Island

1,129

Hawaii

260

False killer whale †

Hawaii Pelagic

2,287

Main Hawaiian Islands Insular †

1,256

Northwestern Hawaiian Islands

837

Fraser's dolphin

Hawaiian

85,193

Killer whale

Eastern North Pacific Offshore

236

Eastern North Pacific Transient/West Coast Transient

438

Hawaiian

279

Long-beaked common dolphin

California

805,063

Melon-headed whale

Hawaiian Islands

7,678

Kohala Resident

1,119

Northern right whale dolphin

California, Oregon, & Washington

280,066

Pacific white-sided dolphin

California, Oregon, & Washington

213,380

Pantropical spotted dolphin

Hawaii Island

9,568

Hawaii Pelagic

24,805

Oahu

1,349

4-Island

2,513

Pygmy killer whale

Hawaiian

18,347

Tropical

1,928

Risso's dolphin

California, Oregon, & Washington

339,334

Hawaiian

19,027

Rough-toothed dolphin

Hawaiian

14,851

NSD

Short-beaked common dolphin

California, Oregon, & Washington

3,795,732

304

Short-finned pilot whale

California, Oregon, & Washington

6,253

Hawaiian

29,269

Spinner dolphin

Hawaii Island

1,394

Hawaii Pelagic

9,534

Kauai & Niihau

9,277

Oahu & 4-Island

1,987

Striped dolphin

California, Oregon, & Washington

371,328

Hawaiian

16,270

Dall's porpoise

California, Oregon, & Washington

115,353

478

California sea lion

U.S.

334,332

Guadalupe fur seal *

Mexico

6,167

Northern fur seal

California

36,921

Harbor seal

California

15,898

Hawaiian monk seal *

Hawaiian

372

Northern elephant seal

California

151,754

187

* ESA-listed species (all stocks) within the HSTT Study Area.

† Only designated stocks are ESA-listed.

NSD: No stock designation.

Estimated Take From Vessel Strikes and Explosives by Serious Injury or Mortality

Vessel Strike

Vessel strikes from commercial, recreational, and military vessels are known to affect large whales and have resulted in serious injury and occasional fatalities to cetaceans (Berman-Kowalewski

et al.,

2010; Calambokidis, 2012; Douglas

et al.,

2008; Laggner 2009; Lammers

et al.,

2003). Records of collisions date back to the early 17th century, and the worldwide number of collisions appears to have increased steadily during recent decades (Laist

et al.,

2001; Ritter 2012).

Numerous studies of interactions between surface vessels and marine mammals have demonstrated that free-ranging marine mammals often, but not always (

e.g.,

McKenna

et al.,

2015), engage in avoidance behavior when surface vessels move toward them. It is not clear whether these responses are caused by the physical presence of a surface vessel, the underwater noise generated by the vessel, or an interaction between the two (Amaral and Carlson, 2005; Au and Green, 2000; Bain

et al.,

2006; Bauer 1986; Bejder

et al.,

1999; Bejder and Lusseau, 2008; Bejder

et al.,

2009; Bryant

et al.,

1984; Corkeron, 1995; Erbe, 2002; Félix, 2001; Goodwin and Cotton, 2004; Lemon

et al.,

2006; Lusseau, 2003; Lusseau, 2006; Magalhaes

et al.,

2002; Nowacek

et al.,

2001; Richter

et al.,

2003; Scheidat

et al.,

2004; Simmonds, 2005; Watkins, 1986; Williams

et al.,

2002; Wursig

et al.,

1998). Several authors suggest that the noise generated during motion is probably an important factor (Blane and Jaakson, 1994; Evans

et al.,

1992; Evans

et al.,

1994). Water disturbance may also be a factor. These studies suggest that the behavioral responses of marine mammals to surface vessels are similar to their behavioral responses to predators. Avoidance behavior is expected to be even stronger in the subset of instances during which the Navy is conducting training or testing activities using active sonar or explosives.

The most vulnerable marine mammals are those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives (

e.g.,

sperm whales). In addition, some baleen whales seem generally unresponsive to vessel sound, making them more susceptible to vessel collisions (Nowacek

et al.,

2004). These species are primarily large, slow moving whales.

Some researchers have suggested the relative risk of a vessel strike can be assessed as a function of animal density and the magnitude of vessel traffic (

e.g.,

Fonnesbeck

et al.,

2008; Vanderlaan

et al.,

2008). Differences among vessel types also influence the probability of a vessel strike. The ability of any ship to detect a marine mammal and avoid a collision depends on a variety of factors, including environmental conditions, ship design, size, speed, and ability and number of personnel observing, as well as the behavior of the animal. Vessel speed, size, and mass are all important factors in determining if injury or death of a marine mammal is likely due to a vessel strike. For large vessels, speed and angle of approach can influence the severity of a strike. For example, Vanderlaan and Taggart (2007) found that between vessel speeds of 8.6 and 15 knots, the probability that a vessel strike is lethal increases from 0.21 to 0.79. Large whales also do not have to be at the water's surface to be struck. Silber

et al.

(2010) found when a whale is below the surface (about one to two times the vessel draft), there is likely to be a pronounced propeller suction effect. This suction effect may draw the whale into the hull of the ship, increasing the probability of propeller strikes.

There are some key differences between the operation of military and non-military vessels, which make the likelihood of a military vessel striking a whale lower than some other vessels (

e.g.,

commercial merchant vessels). Key differences include:

• Many military ships have their bridges positioned closer to the bow, offering better visibility ahead of the ship (compared to a commercial merchant vessel).

• There are often aircraft associated with the training or testing activity (which can serve as Lookouts), which can more readily detect cetaceans in the vicinity of a vessel or ahead of a vessel's present course before crew on the vessel would be able to detect them.

• Military ships are generally more maneuverable than commercial merchant vessels, and if cetaceans are spotted in the path of the ship, could be capable of changing course more quickly.

• The crew size on military vessels is generally larger than merchant ships, allowing for stationing more trained Lookouts on the bridge. At all times when vessels are underway, trained Lookouts and bridge navigation teams are used to detect objects on the surface of the water ahead of the ship, including cetaceans. Additional Lookouts, beyond those already stationed on the bridge and on navigation teams, are positioned as Lookouts during some training events.

• When submerged, submarines are generally slow moving (to avoid detection) and therefore marine mammals at depth with a submarine are likely able to avoid collision with the submarine. When a submarine is transiting on the surface, there are Lookouts serving the same function as they do on surface ships.

Vessel strike to marine mammals is not associated with any specific training or testing activity but is rather an extremely limited and sporadic, but possible, accidental result of Navy vessel movement within the HSTT Study Area or while in transit.

There have been two recorded Navy vessel strikes of large whales in the HSTT Study Area from 2009 through 2018, the period in which the Navy

began implementing effective mitigation measures to reduce the likelihood of vessel strikes. Both strikes occured in 2009 and both were to fin whales. In order to account for the accidental nature of vessel strikes to large whales in general, and the potential risk from any vessel movement within the HSTT Study Area within the seven-year period in particular, the Navy requested incidental takes based on probabilities derived from a Poisson distribution using ship strike data between 2009-2018 in the HSTT Study Area (the time period from when current mitigations were instituted until the Navy conducted the analysis for the 2019 Navy application), as well as historical at-sea days in the HSTT Study Area from 2009-2018 and estimated potential at-sea days for the period from 2018 to 2025 covered by the requested regulations. This distribution predicted the probabilities of a specific number of strikes (n=0, 1, 2, etc.) over the period from 2018 to 2025. The analysis for the period of 2018 to 2023 is described in detail in Chapter 6 of the 2017 Navy application and has been updated for this seven-year proposed rulemaking.

For the same reasons listed above, describing why a Navy vessel strike is comparatively unlikely, it is highly unlikely that a Navy vessel would strike a whale, dolphin, porpoise, or pinniped without detecting it and, accordingly, NMFS is confident that the Navy's reported strikes are accurate and appropriate for use in the analysis. Specifically, Navy ships have multiple Lookouts, including on the forward part of the ship that can visually detect a hit animal, in the unlikely event ship personnel do not feel the strike (which has occasionally occurred). Navy's strict internal procedures and mitigation requirements include reporting of any vessel strikes of marine mammals, and the Navy's discipline, extensive training (not only for detecting marine mammals, but for detecting and reporting any potential navigational obstruction), and strict chain of command give NMFS a high level of confidence that all strikes actually get reported.

The Navy used those two fin whale strikes in their calculations to determine the number of strikes likely to result from their activities (although worldwide strike information, from all Navy activities and other sources, was used to inform the species that may be struck) and evaluated data beginning in 2009, as that was the start of the Navy's Marine Species Awareness Training and adoption of additional mitigation measures to address ship strike, which will remain in place along with additional mitigation measures during the seven years of this rule. The probability analysis concluded that there was a 22 percent chance that zero whales would be struck by Navy vessels over the seven-year period, and a 33, 25, 13, and 5 percent chance that one, two, three, or four whales, respectively, would be struck over the seven-year period (with a 78 percent chance that greater than one whale would be struck over the seven-year period). Therefore, the Navy estimates, and NMFS agrees, that there is some probability that the Navy could strike, and take by serious injury or mortality, up to three large whales incidental to training and testing activities within the HSTT Study Area over the course of the seven years.

The probability of the Navy striking up to three large whales over the seven-year period (which is a 13 percent chance) as analyzed for this proposed rule using updated Navy vessel strike data and at-sea days is very close to the probability of the Navy striking up to three large whales over five years (which was a 10 percent chance). As the probability of striking three large whales does not differ significantly from the 2018 HSTT final rule, and the probability of striking four large whales over seven years remains very low to the point of being unlikely (less than 5 percent), the Navy has requested, and we are proposing, no change in the number of takes by serious injury or mortality due to vessel strikes.

Small delphinids, porpoises, and pinnipeds are not expected to be struck by Navy vessels. In addition to the reasons listed above that make it unlikely that the Navy will hit a large whale (more maneuverable ships, larger crew, etc.), following are the additional reasons that vessel strike of dolphins, small whales, porpoises, and pinnipeds is considered very unlikely. Dating back more than 20 years and for as long as it has kept records, the Navy has no records of individuals of these groups being struck by a vessel as a result of Navy activities and, further, their smaller size and maneuverability make a strike unlikely. Also, NMFS has never received any reports from other authorized activities indicating that these species have been struck by vessels. Worldwide ship strike records show little evidence of strikes of these groups from the shipping sector and larger vessels and the majority of the Navy's activities involving faster-moving vessels (that could be considered more likely to hit a marine mammal) are located in offshore areas where smaller delphinid, porpoise, and pinniped densities are lower. Based on this information, NMFS concurs with the Navy's assessment and recognizes the potential for (and is proposing for authorization) incidental take by vessel strike of large whales only (

i.e.,

no dolphins, small whales, porpoises, or pinnipeds) over the course of the seven-year regulations from training and testing activities as discussed below.

As noted in the 2018 HSTT proposed and final rules, in the 2017 Navy application the Navy initially considered a weight of evidence approach that considered relative abundance, historical strike data over many years, and the overlap of Navy activities with the stock distribution in their request. NMFS and the Navy further discussed the available information and considered two factors in addition to those considered in the Navy's additional request: (1) The relative likelihood of hitting one stock versus another based on available strike data from all vessel types as denoted in the SARs and (2) whether the Navy has ever definitively struck an individual from a particular stock and, if so, how many times. For this seven-year rule, we have reconsidered these two factors and updated the analysis with the Navy's seven-year ship strike probability analysis and any new/updated ship strike data from the SARs.

To address number (1) above, NMFS compiled information from NMFS' SARs on detected annual rates of large whale serious injury or mortality from vessel collisions. The annual rates of large whale serious injury or mortality from vessel collisions from the SARs help inform the relative susceptibility of large whale species to vessel strike in SOCAL and Hawaii as recorded systematically over the last five years (the period used for the SARs). We summed the annual rates of serious injury or mortality from vessel collisions as reported in the SARs, then divided each species' annual rate by this sum to get the relative likelihood. To estimate the percent likelihood of striking a particular species of large whale, we multiplied the relative likelihood of striking each species by the total probability of striking a whale (

i.e.,

78 percent, as described by the Navy's probability analysis above). We also calculated the percent likelihood of striking a particular species of large whale twice by squaring the value estimated for the probability of striking a particular species of whale once (

i.e.,

to calculate the probability of an event occurring twice, multiply the probability of the first event by the second). We note that these probabilities vary from year to year as the average annual mortality for a given five-year window in the SAR changes (and we

include the annual averages from 2017 and 2018 SARs in Table 13 to illustrate), however, over the years and through changing SARs, stocks tend to consistently maintain a relatively higher or relatively lower likelihood of being struck.

The probabilities calculated as described above are then considered in combination with the information indicating the species that the Navy has definitively hit in the HSTT Study Area since 1991 (since they started tracking consistently), as well as the information originally considered by the Navy in their 2017 application, which includes relative abundance, total recorded strikes, and the overlay of all of this information with the Navy's action area. We note that for all of the mortal take of species specifically denoted in Table 13 below, 19 percent of the individuals struck overall by any vessel type remained unidentified and 36 percent of those struck by the Navy (5 of 14 in the Pacific) remained unidentified. However, given the information on known stocks struck, the analysis below remains appropriate. We also note that Rockwood

et al.

(2017) modeled the likely vessel strike of blue whales, fin whales, and humpback whales on the U.S. West Coast (discussed in more detail in the

Serious Injury or Mortality

subsection of the

Preliminary Analysis and Negligible Impact Determination

section), and those numbers help inform the relative likelihood that the Navy will hit those stocks.

For each indicated stock, Table 13 includes the percent likelihood of hitting an individual whale once based on SAR data, total strikes from Navy vessels and from all other vessels, relative abundance, and modeled vessel strikes from Rockwood

et al.

(2017). The last column indicates the annual mortality proposed to be authorized: those stocks with one serious injury or mortality (M/SI) take proposed to be authorized over the seven-year period of the rule are shaded lightly, while those with two M/SI takes proposed to be authorized over the seven-year period of the rule are shaded more darkly.

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Accordingly, stocks that have no record of ever having been struck by any vessel are considered unlikely to be struck by the Navy in the seven-year period of the rule. Stocks that have never been struck by the Navy, have rarely been struck by other vessels, and have a low percent likelihood based on the SAR calculation and a low relative abundance are also considered unlikely to be struck by the Navy during the seven-year rule. We note that while vessel strike records have not differentiated between Eastern North Pacific and Western North Pacific gray whales, given their small population size and the comparative rarity with which individuals from the Western North Pacific stock are detected off the U.S. West Coast, it is highly unlikely that they would be encountered, much less struck. This rules out all but six stocks.

Three of the six stocks (CA/OR/WA stock of fin whale, Eastern North Pacific stock of gray whale, and Central North Pacific stock of humpback whale) are the only stocks to have been hit more than one time each by the Navy in the HSTT Study Area, have the three highest total strike records (21, 35, and 58 respectively), have three of the four highest percent likelihoods based on the SAR records, have three of the four significantly higher relative abundances, and have up to a 3.4 percent likelihood of being struck twice based on NMFS' SAR calculation (not shown in Table 13, but proportional to percent likelihood of being struck once). Based on all of these factors, it is considered reasonably likely that these stocks could be struck twice during the seven-year rule.

Based on the information summarized in Table 13, and the fact that there is the potential for up to three large whales to be struck, it is considered reasonably likely that one individual from the

remaining three stocks could be one of the three whales struck. Sperm whales have only been struck a total of two times by any vessel type in the whole HSTT Study Area, however, the Navy struck a sperm whale once in Hawaii prior to 2009 and the relative abundance of sperm whales in Hawaii is the highest of any of the stocks present. Therefore, we consider it reasonably likely that the Hawaii stock of sperm whales could be struck once during the seven-year rule. The total strikes of Eastern North Pacific blue whales, the percent likelihood of striking one based on the SAR calculation, and their relative abundance can all be considered moderate compared to other stocks, and the Navy has struck one in the past prior to 2009 (with the likelihood of striking two based on the SAR calculation being below one percent). Therefore, we consider it reasonably likely that the Navy could strike one individual over the course of the seven-year rule. The Navy has not hit a humpback whale in the HSTT Study Area and the relative abundance of the CA/OR/WA stock is very low. However, the Navy has struck a humpback whale in the Northwest and as a species, humpbacks have a moderate to high number of total strikes and percent likelihood of being struck. Although the likelihood of CA/OR/WA humpback whales being struck overall is moderate to high relative to other stocks, the distribution of the Mexico DPS versus the Central America DPS, as well as the distribution of overall vessel strikes inside versus outside of the SOCAL area (the majority are outside), supports the reasonable likelihood that the Navy could strike one individual humpback whale from the CA/OR/WA stock (not two), and that that individual would be highly likely to be from the Mexico DPS, as described below.

Specifically, regarding the likelihood of striking a humpback whale from a particular DPS, as suggested in Wade

et al.

(2016), the probability of encountering (which is thereby applied to striking) humpback whales from each DPS in the CA/OR area is 89.6 percent and 19.7 percent for the Mexico and Central America DPSs, respectively (note that these percentages reflect the upper limit of the 95 percent confidence interval to reduce the likelihood of underestimating take, and thereby do not total to 100). This suggests that the chance of striking a humpback whale from the Central America DPS is one tenth to one fifth of the overall chance of hitting a CA/OR/WA humpback whale in general in the SOCAL part of the HSTT Study Area, which in combination with the fact that no humpback whale has been struck in SOCAL makes it highly unlikely, and thereby no strikes of whales from the Central America DPS are anticipated or authorized. If a humpback whale were struck in SOCAL, it is likely it would be of the Mexico DPS. However, regarding the overall likelihood of striking a humpback whale at all and the likely number of times, we note that the majority of strikes of the CA/OR/WA humpback whale (

i.e.,

the numbers reflected in Table 13) take place outside of SOCAL and, whereas the comparative DPS numbers cited above apply in the California and Oregon feeding area, in the Washington and Southern British Columbia feeding area, Wade

et al.

(2016) suggest that 52.9, 41.9, and 14.7 percent of humpback whales encountered will come from the Hawaii, Mexico, and Central America DPSs, respectively. This means that the numbers in Table 13 indicating the overall strikes of CA/OR/WA humpback whales and SAR calculations based on average annual mortality over the last five years are actually lower than indicated for the Mexico DPS, which would only be a subset of those mortalities. Last, the Rockwood

et al.

paper supports a relative likelihood of 1:1:2 for striking blue whales, humpback whales, and fin whales off the U.S. West Coast, which supports the proposed authorized take included in this rule, which is 1, 1, and 2, respectively over the seven-year period. For these reasons, one mortal take of CA/OR/WA humpback whales, which would be expected to be of the Mexico DPS, could reasonably likely occur and is proposed for authorization.

Accordingly, the Navy has requested take by M/SI from vessel strike of up to two of any of the following species/stocks in the seven-year period: gray whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), humpback whale (Central North Pacific stock); and one of any of the following species/stocks in the seven-year period: Blue whale (Eastern North Pacific stock), humpback whale (CA/OR/WA stock, Mexico DPS), or sperm whale (Hawaii stock).

As described above, the Navy analysis suggests, and NMFS analysis concurs, that vessel strikes to the stocks below are very unlikely to occur due to the stocks' relatively low occurrence in the HSTT Study Area, particularly in core HSTT training and testing subareas, and the fact that the stocks have not been struck by the Navy and are rarely, if ever, recorded struck by other vessels. Therefore the Navy is not requesting lethal take authorization, and NMFS is not proposing to authorize lethal take, for the following stocks: Bryde's whale (Eastern Tropical Pacific stock), Bryde's whale (Hawaii stock), humpback whale (CA/OR/WA stock, Central America DPS), minke whale (CA/OR/WA stock), minke whale (Hawaii stock), sei whale (Hawaii stock), sei whale (Eastern North Pacific stock), and sperm whale (CA/OR/WA stock).

In conclusion, although it is generally unlikely that any whales will be struck in a year, based on the information and analysis above, NMFS anticipates that there is the potential of no more than three whales taken by M/SI over the seven-year period of the rule, and that those three whales may include no more than two of any of the following stocks: Gray whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), and humpback whale (Central North Pacific stock); and no more than one of any of the following stocks: Blue whale (Eastern North Pacific stock), humpback whale (CA/OR/WA, Mexico DPS), and sperm whale (Hawaii stock). Accordingly, NMFS has evaluated under the negligible impact standard the M/SI of 0.14 or 0.29 whales annually from each of these species or stocks (

i.e.,

1 or 2 takes, respectively, divided by seven years to get the annual number), along with the expected incidental takes by harassment.

Explosives

The Navy's model and quantitative analysis process used for the 2018 HSTT FEIS/OEIS and in the Navy's 2017 and 2019 applications to estimate potential exposures of marine mammals to explosive stressors is detailed in the technical report titled

Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing Report

(U.S. Department of the Navy, 2018). Specifically, over the course of a modelled maximum year of training and testing, the Navy's model and quantitative analysis process estimates M/SI of two short-beaked common dolphin and one California sea lion as a result of exposure to explosive training and testing activities (please see Section 6 of the 2017 Navy application where it is explained how maximum annual estimates are calculated). Over the five‐year period of the 2018 HSTT regulations, mortality of 6 short-beaked common dolphins and 4 California sea lions was estimated and authorized (10 marine mammals in total) as a result of exposure to explosive training and testing activities. In extending the same training and testing activities for an additional two years, over the seven‐year period of the proposed

regulations M/SI of 8 short-beaked common dolphins and 5 California sea lions (13 marine mammals in total) is estimated as a result of exposure to explosive training and testing activities. As explained in the aforementioned Analytical Approach technical report, expected impacts were calculated considering spatial and seasonal differences in model inputs, as well as the expected variation in the number of training and testing events from year to year, described as representative and maximum levels of activity. The summed impacts over any multi-year period, therefore, are the expected value for impacts over that time period rather than a multiple of a single maximum year's impacts. Therefore, calculating the seven-year total is not a matter of simply multiplying the annual estimate by seven, as the total amount of estimated mortalities over the seven years covered by the 2019 Navy application is less than the sum total of each year. As explained earlier, although the annual estimates are based on the maximum number of activities per year and therefore the maximum estimated takes, the seven-year total take estimates are based on the sum of three maximum years and four representative years. NMFS coordinated with the Navy in the development of their take estimates and concurs with the Navy's approach for estimating the number of animals from each species or stock that could be taken by M/SI from explosives.

Proposed Mitigation Measures

Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to the activity, and other means of effecting the least practicable adverse impact on the species or stock(s) and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stock(s) for subsistence uses (“least practicable adverse impact”). NMFS does not have a regulatory definition for least practicable adverse impact. The 2004 NDAA amended the MMPA as it relates to military readiness activities and the incidental take authorization process such that a determination of “least practicable adverse impact” shall include consideration of personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. For the full discussion of how NMFS interprets least practicable adverse impact, including how it relates to the negligible-impact standard, see the

Mitigation Measures

section in the 2018 HSTT final rule.

Section 101(a)(5)(A)(i)(II) requires NMFS to issue, in conjunction with its authorization, binding—and enforceable—restrictions (in the form of regulations) setting forth how the activity must be conducted, thus ensuring the activity has the “least practicable adverse impact” on the affected species or stocks. In situations where mitigation is specifically needed to reach a negligible impact determination, section 101(a)(5)(A)(i)(II) also provides a mechanism for ensuring compliance with the “negligible impact” requirement. Finally, the least practicable adverse impact standard also requires consideration of measures for marine mammal habitat, with particular attention to rookeries, mating grounds, and other areas of similar significance, and for subsistence impacts, whereas the negligible impact standard is concerned solely with conclusions about the impact of an activity on annual rates of recruitment and survival.

In evaluating what mitigation measures are appropriate, NMFS considers the potential impacts of the Specified Activities, the availability of measures to minimize those potential impacts, and the practicability of implementing those measures, as we describe below.

Outside of the military readiness context, mitigation may also be appropriate to ensure compliance with the “small numbers” language in MMPA sections 101(a)(5)(A) and (D).

Implementation of Least Practicable Adverse Impact Standard

Our evaluation of potential mitigation measures includes consideration of two primary factors:

(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, their habitat, and their availability for subsistence uses (where relevant). This analysis considers such things as the nature of the potential adverse impact (such as likelihood, scope, and range), the likelihood that the measure will be effective if implemented, and the likelihood of successful implementation; and

(2) The practicability of the measures for applicant implementation. Practicability of implementation may consider such things as cost, impact on activities, and, in the case of a military readiness activity, specifically considers personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. 16 U.S.C. 1371(a)(5)(A)(iii).

While the language of the least practicable adverse impact standard calls for minimizing impacts to affected species or stocks, we recognize that the reduction of impacts to those species or stocks accrues through the application of mitigation measures that limit impacts to individual animals. Accordingly, NMFS' analysis focuses on measures that are designed to avoid or minimize impacts on individual marine mammals that are likely to increase the probability or severity of population-level effects.

While direct evidence of impacts to species or stocks from a specified activity is rarely available, and additional study is still needed to understand how specific disturbance events affect the fitness of individuals of certain species, there have been improvements in understanding the process by which disturbance effects are translated to the population. With recent scientific advancements (both marine mammal energetic research and the development of energetic frameworks), the relative likelihood or degree of impacts on species or stocks may often be inferred given a detailed understanding of the activity, the environment, and the affected species or stocks—and the best available science has been used here. This same information is used in the development of mitigation measures and helps us understand how mitigation measures contribute to lessening effects (or the risk thereof) to species or stocks. We also acknowledge that there is always the potential that new information, or a new recommendation could become available in the future and necessitate reevaluation of mitigation measures (which may be addressed through adaptive management) to see if further reductions of population impacts are possible and practicable.

In the evaluation of specific measures, the details of the specified activity will necessarily inform each of the two primary factors discussed above (expected reduction of impacts and practicability), and are carefully considered to determine the types of mitigation that are appropriate under the least practicable adverse impact standard. Analysis of how a potential mitigation measure may reduce adverse impacts on a marine mammal stock or species, consideration of personnel safety, practicality of implementation, and consideration of the impact on effectiveness of military readiness activities are not issues that can be meaningfully evaluated through a yes/no lens. The manner in which, and the degree to which, implementation of a measure is expected to reduce impacts, as well as its practicability in terms of these considerations, can vary widely.

For example, a time/area restriction could be of very high value for decreasing population-level impacts (

e.g.,

avoiding disturbance of feeding females in an area of established biological importance) or it could be of lower value (

e.g.,

decreased disturbance in an area of high productivity but of less firmly established biological importance). Regarding practicability, a measure might involve restrictions in an area or time that impede the Navy's ability to certify a strike group (higher impact on mission effectiveness), or it could mean delaying a small in-port training event by 30 minutes to avoid exposure of a marine mammal to injurious levels of sound (lower impact). A responsible evaluation of “least practicable adverse impact” will consider the factors along these realistic scales. Accordingly, the greater the likelihood that a measure will contribute to reducing the probability or severity of adverse impacts to the species or stock or its habitat, the greater the weight that measure is given when considered in combination with practicability to determine the appropriateness of the mitigation measure, and vice versa. In the evaluation of specific measures, the details of the specified activity will necessarily inform each of the two primary factors discussed above (expected reduction of impacts and practicability), and will be carefully considered to determine the types of mitigation that are appropriate under the least practicable adverse impact standard. For more detail on how we apply these factors, see the discussion in the

Mitigation Measures

section of the 2018 HSTT final rule.

NMFS fully reviewed the Navy's specified activities and the mitigation measures for the 2018 HSTT rulemaking and determined that the mitigation measures would result in the least practicable adverse impact on marine mammals. There is no change in either the activities or the mitigation measures for this rule. See the 2019 Navy application and the 2018 HSTT final rule for detailed information on the Navy's mitigation measures. NMFS worked with the Navy in the development of the Navy's initially proposed measures, which were informed by years of implementation and monitoring. A complete discussion of the Navy's evaluation process used to develop, assess, and select mitigation measures, which was informed by input from NMFS, can be found in Chapter 5 (

Mitigation

) of the 2018 HSTT FEIS/OEIS. The process described in Chapter 5 (

Mitigation

) of the 2018 HSTT FEIS/OEIS robustly supported NMFS' independent evaluation of whether the mitigation measures would meet the least practicable adverse impact standard. The Navy has implemented the mitigation measures under the 2018 HSTT regulations and would be required to continue implementation of the mitigation measures identified in this rule for the full seven years it covers to avoid or reduce potential impacts from acoustic, explosive, and physical disturbance and ship strike stressors.

In its 2019 application, the Navy proposes no changes to the mitigation measures in the 2018 HSTT final rule and there is no new information that affects NMFS' assessment of the applicability or effectiveness of those measures over the new seven-year period. See the 2018 HSTT proposed rule and the 2018 HSTT final rule for our full assessment of these measures. In summary, the Navy has agreed to procedural mitigation measures that will reduce the probability and/or severity of impacts expected to result from acute exposure to acoustic sources or explosives, ship strike, and impacts to marine mammal habitat. Specifically, the Navy will use a combination of delayed starts, powerdowns, and shutdowns to minimize or avoid M/SI minimize the likelihood or severity of PTS or other injury, and reduce instances of TTS or more severe behavioral disruption caused by acoustic sources or explosives. The Navy will also implement multiple time/area restrictions (several of which were added in the 2018 HSTT final rule since the previous HSTT MMPA incidental take rule) that would reduce take of marine mammals in areas or at times where they are known to engage in important behaviors, such as feeding or calving, where the disruption of those behaviors would have a higher probability of resulting in impacts on reproduction or survival of individuals that could lead to population-level impacts. Summaries of the Navy's procedural mitigation measures and mitigation areas for the HSTT Study Area are provided in Tables 14 and 15.

Table 14—Summary of Procedural Mitigation

Stressor or activity

Mitigation zone sizes and other requirements

Environmental Awareness and Education

• Afloat Environmental Compliance Training program for applicable personnel.

Active Sonar

Depending on sonar source:

• 1,000 yd power down, 500 yd power down, and 200 yd shut down.

• 200 yd shut down.

Air Guns

• 150 yd.

Pile Driving

• 100 yd.

Weapons Firing Noise

• 30 degrees on either side of the firing line out to 70 yd.

Explosive Sonobuoys

• 600 yd.

Explosive Torpedoes

• 2,100 yd.

Explosive Medium-Caliber and Large-Caliber Projectiles

• 1,000 yd (large-caliber projectiles).

• 600 yd (medium-caliber projectiles during surface-to-surface activities).

• 200 yd (medium-caliber projectiles during air-to-surface activities).

Explosive Missiles and Rockets

• 2,000 yd (21-500 lb. net explosive weight).

• 900 yd (0.6-20 lb. net explosive weight).

Explosive Bombs

• 2,500 yd.

Sinking Exercises

• 2.5 nmi.

Explosive Mine Countermeasure and Neutralization Activities

• 2,100 yd (6-650 lb net explosive weight).

• 600 yd (0.1-5 lb net explosive weight).

Explosive Mine Neutralization Activities Involving Navy Divers

• 1,000 yd (21-60 lb net explosive weight for positive control charges and charges using time-delay fuses).

• 500 yd (0.1-20 lb net explosive weight for positive control charges).

Underwater Demolition Multiple Charge—Mat Weave and Obstacle Loading

• 700 yd.

Maritime Security Operations—Anti-Swimmer Grenades

• 200 yd.

Vessel Movement

• 500 yd (whales).

• 200 yd (other marine mammals).

Towed In-Water Devices

• 250 yd (marine mammals).

Small-, Medium-, and Large-Caliber Non-Explosive Practice Munitions

• 200 yd.

Non-Explosive Missiles and Rockets

• 900 yd.

Non-Explosive Bombs and Mine Shapes

• 1,000 yd.

Notes:

lb: Pounds; nmi: Nautical miles; yd: Yards.

Table 15—Summary of Mitigation Areas for Marine Mammals

Summary of Mitigation Area Requirements

Hawaii Island Mitigation Area (year-round):

• Navy personnel must not conduct more than 300 hours of MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours of MF4 dipping sonar, or use explosives that could potentially result in takes of marine mammals during training and testing.

4-Islands Region Mitigation Area (November 15-April 15 for active sonar; year-round for explosives):

• Navy personnel must not use MF1 surface ship hull-mounted mid-frequency active sonar or explosives that could potentially result in takes of marine mammals during training and testing.

Humpback Whale Special Reporting Areas (December 15-April 15):

• Navy personnel must report the total hours of surface ship hull-mounted mid-frequency active sonar used in in the special reporting areas in its annual training and testing activity reports submitted to NMFS.

San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach Mitigation Areas (June 1-October 31):

• Navy personnel must not conduct more than a total of 200 hours of MF1 surface ship hull-mounted mid-frequency active sonar in the combined areas, excluding normal maintenance and systems checks, during training and testing.

• Within the San Diego Arc Mitigation Area, Navy personnel must not use explosives that could potentially result in the take of marine mammals during large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training and testing.

• Within the San Nicolas Island Mitigation Area, Navy personnel must not use explosives that could potentially result in the take of marine mammals during mine warfare, large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training.

• Within the Santa Monica/Long Beach Mitigation Area, Navy personnel must not use explosives that could potentially result in the take of marine mammals during mine warfare, large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training and testing.

Santa Barbara Island Mitigation Area (year-round):

• Navy personnel must not use MF1 surface ship hull-mounted mid-frequency active sonar during training and testing, or explosives that could potentially result in the take of marine mammals during medium-caliber or large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training.

Awareness Notification Message Areas (seasonal according to species):

• Navy personnel must issue awareness notification messages to alert ships and aircraft to the possible presence of humpback whales (November-April), blue whales (June-October), gray whales (November-March), or fin whales (November-May).

If Naval units need to conduct more than the specified amount of training or testing, they will obtain permission from the appropriate designated Command authority prior to commencement of the activity. The Navy will provide NMFS with advance notification and include the information in its annual activity reports submitted to NMFS.

Mitigation Conclusions

NMFS has carefully evaluated the Navy's proposed mitigation measures—many of which were developed with NMFS' input during the previous phases of Navy training and testing authorizations and none of which have changed since our evaluation during the 2018 HSTT rulemaking—and considered a broad range of other measures (

i.e.,

the measures considered but eliminated in the 2018 HSTT FEIS/OEIS, which reflect many of the comments that have arisen via NMFS or public input in past years) in the context of ensuring that NMFS prescribes the means of effecting the least practicable adverse impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another: the manner in which, and the degree to which, the successful implementation of the mitigation measures is expected to reduce the likelihood and/or magnitude of adverse impacts to marine mammal species and stocks and their habitat; the proven or likely efficacy of the measures; and the practicability of the measures for applicant implementation, including consideration of personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. There is no new information that affects our analysis from the 2018 HSTT rulemaking, all of which remains applicable and valid for our assessment of the appropriateness of the mitigation measures during the seven-year period of this rule.

Based on our evaluation of the Navy's proposed measures (which are being implemented under the 2018 HSTT regulations), as well as other measures considered by the Navy and NMFS, NMFS has preliminarily determined that the Navy's proposed mitigation measures (which are identical to those in the 2018 HSTT final rule) are appropriate means of effecting the least practicable adverse impact on marine mammal species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and considering specifically personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. Additionally, as described in more detail below, the 2018 HSTT final rule includes an adaptive management

provision, which the Navy proposes to extend, which ensures that mitigation is regularly assessed and provides a mechanism to improve the mitigation, based on the factors above, through modification as appropriate.

The proposed rule comment period provides the public an opportunity to submit recommendations, views, and/or concerns regarding the Navy's activities and the proposed mitigation measures. While NMFS has preliminarily determined that the Navy's proposed mitigation measures would effect the least practicable adverse impact on the affected species or stocks and their habitat, NMFS will consider all public comments to help inform our final decision. Consequently, the proposed mitigation measures may be refined, modified, removed, or added to prior to the issuance of the final rule based on public comments received, and where appropriate, further analysis of any additional mitigation measures.

Proposed Monitoring

Section 101(a)(5)(A) of the MMPA states that in order to authorize incidental take for an activity, NMFS must set forth requirements pertaining to the monitoring and reporting of such taking. The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for incidental take authorizations must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present.

In its 2019 application, the Navy proposes no changes to the monitoring described in the 2018 HSTT final rule. They would continue implementation of the robust Integrated Comprehensive Monitoring Program and Strategic Planning Process described in the 2018 HSTT final rule. The Navy's monitoring strategy, currently required by the 2018 HSTT regulations, is well-designed to work across Navy ranges to help better understand the impacts of the Navy's activities on marine mammals and their habitat by focusing on learning more about marine mammal occurrence in different ar

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