Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Testing and Training Operations in the Eglin Gulf Test and Training Range

Federal RegisterApr 18, 2023

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 230410-0096]

RIN 0648-BL77

Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Testing and Training Operations in the Eglin Gulf Test and Training Range

AGENCY:

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

ACTION:

Final rule; notification of issuance of Letters of Authorization.

SUMMARY:

NMFS, upon request from the U.S. Department of the Air Force (USAF), issues these regulations pursuant to the Marine Mammal Protection Act (MMPA) to govern the taking of marine mammals incidental to testing and training activities to be conducted in the Eglin Gulf Test and Training Range (EGTTR) from 2023 to 2030 in the Gulf of Mexico. The USAF's activities qualify as military readiness activities pursuant to the MMPA, as amended by the National Defense Authorization Act for Fiscal Year 2004 (2004 NDAA). These regulations, which allow for the issuance of Letters of Authorization (LOA) for the incidental take of marine mammals during the described activities and timeframes, prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species and their habitat, and establish requirements pertaining to the monitoring and reporting of such taking.

DATES:

Effective dates:

Amendatory instruction 1 is effective April 13, 2023, and amendatory instruction 2 is effective from April 13, 2023, through April 13, 2030.

Applicability dates:

This rule is applicable to the USAF on April 13, 2023, through April 13, 2030.

ADDRESSES:

A copy of the USAF's application, NMFS' proposed and final rules and subsequent LOA for the existing regulations, and other supporting documents and documents cited herein may be obtained online at

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

In case of problems accessing these documents, please use the contact listed here (see

FOR FURTHER INFORMATION CONTACT

FOR FURTHER INFORMATION CONTACT:

Robert Pauline, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose of Regulatory Action

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

et seq.

), provide the framework for authorizing the take of marine mammals incidental to the USAF's testing and training activities (which qualify as military readiness activities) from air-to-surface operations that involve firing live or inert munitions, including missiles, bombs, and gun ammunition, from aircraft at various types of targets on the water surface. Live munitions used in the EGTTR are set to detonate either in the air a few feet above the water, instantaneously upon contact with the water or target, or approximately 5 to 10 feet (ft) (1.5 to 3 meters (m)) below the water surface. There will also be training exercises for Navy divers that require the placement of small explosive charges by hand to disable live mines.

Eglin Air Force Base (AFB) will conduct operations in the existing Live Impact Area (LIA). In addition, the USAF will also create and use a new, separate LIA within the EGTTR that would be used for live missions in addition to the existing LIA. Referred to as the East LIA, it is located approximately 40 nautical miles (nmi) (74 kilometers (km)) southeast of the existing LIA.

NMFS received an application from the USAF requesting 7-year regulations and an authorization to incidentally take individuals of multiple species of marine mammals (“USAF's rulemaking/LOA application” or “USAF's application”). Take is anticipated to occur by Level A and Level B harassment incidental to the USAF's training and testing activities, with no serious injury or mortality expected or authorized.

Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if, after notice and public comment, the agency makes certain findings and issues regulations that set forth permissible methods of taking pursuant to that activity, as well as monitoring and reporting requirements. Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I, provide the legal basis for issuing this final rule and the subsequent LOAs. As directed by this legal authority, this final rule contains mitigation, monitoring, and reporting requirements.

The 2004 NDAA (Pub. L. 108-136) removed the “small numbers” and “specified geographical region” limitations indicated above and amended the definition of “harassment” as applied to a “military readiness activity.” The activity for which incidental take of marine mammals is being requested addressed here qualifies as a 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 7 years. Prior to this amendment, all incidental take rules under section 101(a)(5)(A) were limited to 5 years.

Summary of Major Provisions Within the Final Rule

The following is a summary of the primary provisions of this final rule regarding the USAF's activities. These provisions include, but are not limited to:

• Use of live munitions with surface or subsurface detonations is restricted to the existing Live Impact Area (LIA) and the new East LIA;

• Use of live munitions in the western part of the existing LIA and new East LIA is restricted based on specified setbacks from the 100-meter isobath. The 100-m isobath is the minimum depth at which the majority of Rice's whale detections have occurred. The setbacks are equivalent to the modeled threshold distances where each mission-day category would cause the onset of permanent threshold shift (PTS) in the Rice's whale;

• Use of inert munitions is prohibited between the 100-meter to 400-meter isobaths throughout the EGTTR, which encompasses the area in which the vast majority of Rice's whale detections have occurred;

• Gunnery missions must be conducted at least 500 meters landward of the 100-meter isobath; and

• Use of 105 mm Training Rounds (TR) containing decreased explosive material is required during live nighttime gunnery missions.

• Use of vessel-based, aerial-based and video-based monitoring platforms for mission activities;

• Employment of protected species observers (PSOs) who have completed Eglin's Marine Species Observer Training Course developed in cooperation with NMFS;

• Implementing two passive acoustic monitoring (PAM) studies (pending availability of funding); and

• Submission of annual and final comprehensive monitoring reports that will record all occurrences of marine mammals and any behavior or behavioral reactions observed, any observed incidents of injury or behavioral harassment, and any required mission delays, relocations or cancellations.

Additionally, the rule includes an adaptive management component that allows for timely modification of mitigation or monitoring measures based on new information, when appropriate.

Background

The MMPA prohibits the “take” of marine mammals, with certain exceptions. Sections 101(a)(5)(A) and (D) of the MMPA direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of proposed authorization is provided to the public for review and the opportunity to submit comments.

An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stocks and will not have an unmitigable adverse impact on the availability of the species or stocks for taking for subsistence uses where relevant, including by Alaska Natives. Further, NMFS must prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stocks for taking for certain subsistence uses (referred to in this rule as “mitigation measures”); and requirements pertaining to the monitoring and reporting of such takings. The MMPA defines “take” to mean to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal. The Analysis and Negligible Impact Determination section below discusses the definition of “negligible impact.”

The NDAA for Fiscal Year 2004 (2004 NDAA) (Pub. L. 108-136) amended section 101(a)(5) of the MMPA to remove the “small numbers” and “specified geographical region” provisions indicated above and amended the definition of “harassment” as applied to a “military readiness activity.” The definition of harassment for military readiness activities (section 3(18)(B) of the MMPA) is (i) Any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild (Level A Harassment); or (ii) Any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered (Level B harassment). In addition, the 2004 NDAA amended the MMPA as it relates to military readiness activities such that the least practicable adverse impact analysis shall include consideration of personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity.

Summary and Background of Request

On January 18, 2022, NMFS received an application from the USAF for authorization to take marine mammals by Level A and Level B harassment incidental to training and testing activities (categorized as military readiness activities) in the EGTTR for a period of 7 years. On June 17, 2022, NMFS received an adequate and complete application for missions that would include air-to-surface operations that involve firing live or inert munitions, including missiles, bombs, and gun ammunition from aircraft at targets on the water surface. The types of targets used vary by mission and primarily include stationary, remotely controlled, and towed boats, inflatable targets, and marker flares. Live munitions used in the EGTTR are set to detonate either in the air a few feet above the water surface (airburst detonation), instantaneously upon contact with the water or target (surface detonation), or approximately 5 to 10 feet (1.5 to 3 m) below the water surface (subsurface detonation). On July 17, 2022, we published a notice of receipt (NOR) of application in the

Federal Register

(87 FR 42711), requesting comments and information related to the USAF's request. The public comment period was open for 30 days. We reviewed and considered all comments and information received on the NOR in development of this final rule. On February 7, 2023, we published a notice of proposed rulemaking (88 FR 8146) and requested comments and information related to the USAF's request for 30 days. All substantive comments received during the NOR and the proposed rulemaking comment periods were considered in developing this final rule. Comments received on the proposed rule are addressed in this final rule in the Comments and Responses section.

This is the second time NMFS has promulgated incidental take regulations pursuant to the MMPA relating to similar military readiness activities in the EGTTR. On February 8, 2018, NMFS promulgated a rulemaking and issued an LOA for takes of marine mammals incidental to Eglin AFB's training and testing operations in the EGTTR (83 FR 5545).

Most operations during the current effective period are a continuation of the same operations conducted by the same military units during the previous mission period. There will, however, be an increase in the annual quantities of all general categories of munitions (bombs, missiles, and gun ammunition) under the USAF's planned activities, except for live gun ammunition, which will be used less over the next mission period. The highest net explosive weight (NEW) of the munitions under the USAF's activities will be 945 pounds (lb) (430 kilograms (kg)), which was also the highest NEW for the previous mission period. Live missions planned for the 2023-2030 period will be conducted in the existing Live Impact Area (LIA) within the EGTTR. Certain missions may also be conducted in the East LIA, which is a new, separate area within the EGTTR where live and inert munitions will be used.

The USAF's rulemaking/LOA application reflects the most up-to-date compilation of training and testing activities deemed necessary to accomplish military readiness requirements. EGTTR training and testing operations are critical for achieving military readiness and the overall goals of the National Defense Strategy. The regulations cover testing

and training activities in the EGTTR and will be effective for seven years, beginning from the date of issuance.

Description of the Specified Activity

A detailed description of the specified activity was provided in our

Federal Register

notice of proposed rulemaking (88 FR 8146; February 7, 2023); please see that notice of proposed rulemaking or the USAF's application for more information. The USAF requested authorization to take marine mammals incidental to conducting training and testing activities in the EGTTR. The USAF 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, qualify as take under the MMPA, and NMFS concurs with this determination. Eglin plans to conduct military aircraft missions within the EGTTR that involve the employment of multiple types of live (explosive) and inert (non-explosive) munitions (

i.e.,

missiles, bombs, and gun ammunition) against various surface targets. Munitions may be delivered by multiple types of aircraft including, but not limited to, fighter jets, bombers, and gunships.

Detailed descriptions of these activities are described in the Eglin Gulf Test and Training Range (EGTTR) Range rulemaking/LOA application (

https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-air-force-eglin-gulf-testing-and-training

) and are summarized here.

Dates and Duration

The specified activities will occur at any time during the 7-year period of validity of the regulations. The planned amount of training and testing activities are described in the Detailed Description of the Specified Activities section.

Geographical Region

The Eglin Military Complex encompasses approximately 724 square miles (1,825 km

of land in the Florida Panhandle and consists of the Eglin Reservation in Santa Rosa, Okaloosa, and Walton Counties, and property on Santa Rosa Island and Cape San Blas. The EGTTR is the airspace controlled by Eglin AFB over the Gulf of Mexico, beginning 3 nautical miles (nmi) (5.56 km) from shore, and the underlying Gulf of Mexico waters. The EGTTR extends southward and westward off the coast of Florida and encompasses approximately 102,000 nmi (349,850 km

). It is subdivided into blocks of airspace that consist of Warning Areas W-155, W-151, W-470, W-168, and W-174 and Eglin Water Test Areas 1 through 6 (Figure 1). Most of the blocks are further subdivided into smaller airspace units for scheduling purposes (for example, W-151A, B, C, and D). Although Eglin AFB may use any portion of the EGTTR, the majority of training and testing operations planned for the 2023-2030 mission period would occur in Warning Area W-151. The nearshore boundary of W-151 parallels much of the coastline of the Florida Panhandle and extends horizontally from 3 nmi (5.56 km) offshore to approximately 85 to 100 nmi (158 to185 km) to offshore, depending on the specific portion of its outer boundary. W-151 encompasses approximately 10,247 nmi

(35146 km

) and includes water depths that range from approximately 5 to 720 m. The existing LIA, which is the portion of the EGTTR where the use of live munitions is currently authorized, lies mostly within W-151. The existing LIA encompasses approximately 940 nmi

(3,224 km

) and includes water depths that range from approximately 30 to 145 m. This is where live munitions within the EGTTR are currently used in the existing LOA (83 FR 5545; February 8, 2018) and where the Gulf Range Armament Test Vessel (GRATV) is anchored. The GRATV remains anchored at a specific location during a given mission; however, it is mobile and relocated within the LIA based on mission needs.

The USAF's planned activities provide for the creation of a new, separate area within the EGTTR that will be used for live missions in addition to the existing LIA. This area, herein referred to as the East LIA, is located approximately 40 nmi offshore of Eglin AFB property on Cape San Blas. Cape San Blas is located on St. Joseph Peninsula in Gulf County, Florida, approximately 90 mi (144 km) southeast of the Eglin Reservation. Eglin AFB facilities on Cape San Blas remotely support EGTTR operations via radar tracking, telemetry, and other functions. The East LIA is circular-shaped and has a radius of approximately 10 nmi (18.5 km) and a total area of approximately 314 nmi

. Water depths range from approximately 35 to 95 m. The East LIA will allow Eglin AFB to maximize the flight range for large-footprint weapons and minimize the distance, time, and cost of deploying support vessels and targets. Based on these factors, the East LIA will allow testing of weapon systems and flight profiles that cannot be conducted within the constraints of the existing LIA.

Detailed Description of the Specified Activities

This section provides descriptions of each military user group's planned EGTTR operations, as well as information regarding munitions planned to be used during the operations. This information includes munition type, category, net explosive weight (NEW), detonation scenario, and annual quantity planned to be expended in the EGTTR. NEW applies only to live munitions and is the total mass of the explosive substances in a given munition, without packaging, casings, bullets, or other non-explosive components of the munition. Note that for some munitions the warhead is removed and replaced with a telemetry package that tracks the munition's path and/or Flight Termination System (FTS) that ends the flight of the munition in a controlled manner. These munitions have been categorized as live munitions with NEWs that range from 0.30 to 0.70 lb (0.13 to 0.31 kg). While certain munitions with only FTS may be considered inert due to negligible NEW, those contained here are considered to be live with small amounts of NEW. The detonation scenario applies only to live munitions which are set to detonate in one of three ways: (1) in the air a few feet above the water surface, referred to as airburst or height of burst (HOB); (2) instantaneously upon contact with the water or target on the water surface; or (3) after a slight delay, up to 10 milliseconds, after impact, which would correspond to a subsurface detonation at a water depth of approximately 5 to 10 ft (1.5 to 3 m). Estimated take is only modeled for scenarios (2) and (3). The planned annual expenditures of munitions are the quantities determined necessary to meet the mission requirements of the user groups.

Live missions planned for the 2023-2030 period would be conducted in the existing LIA and the East LIA, depending on the mission type and objectives. Live missions that involve only airburst or aerial target detonations would continue to be conducted in or outside the LIA in any portion of the EGTTR; such detonations have no appreciable effect on marine mammals because there is negligible transmission of pressure or acoustic energy across the air-water interface. Use of inert munitions and live air-to-surface gunnery operations would also continue to occur in or outside the LIA, subject to required mitigation and monitoring measures.

Eglin AFB plans to implement the following actions in the EGTTR which would be conducted in the existing LIA

and the East LIA, depending on the mission type and objectives:

(1) 53rd Weapons Evaluation Group missions that involve air-to-surface tests various types of munitions against small target boats, and air-to-air missile testing;

(2) Continuation of the Air Force Special Operations Command (AFSOC) training missions in the EGTTR primarily involving air-to-surface gunnery, bomb, and missile exercises including AC-130 gunnery training, CV-22 training, and bomb and missile training;

(3) 96th Operations Group missions including AC-130 gunnery testing against floating marker targets on the water surface, and other aircraft air-to-surface testing; and 780th Test Squadron weapons testing of air-launched cruise missiles, air-to-air missiles, air-to-surface missiles, and surface-to-air missiles using live and inert munitions against targets on the water surface; and

(4) Naval School Explosive Ordnance Disposal (NAVSCOLEOD) training missions that involve students diving and placing small explosive charges adjacent to inert mines.

53rd Weapons Evaluation Group

The 53rd Weapons Evaluation Group (53 WEG) conducts the USAF's air-to-ground Weapons System Evaluation Program (WSEP) for testing various types of live and inert munitions against small target boats. This testing is conducted to develop tactics, techniques, and procedures (TTP) to be used by USAF aircraft to counter small, maneuvering, hostile vessels. Missions planned in the EGTTR for the 2023-2030 period would involve the use of several types of aircraft. USAF, Air National Guard, and U.S. Navy units would support these missions. Live munitions would be deployed against static (anchored), remotely controlled, and towed targets. Static and remotely controlled targets would consist of stripped boat hulls with simulated systems and, in some cases, heat sources. Various types of live and inert munitions are used during 53 WEG missions in the EGTTR, including missiles, bombs, and gun ammunition. Table 1 presents information on the munitions planned for 53 WEG air-to-surface missions in the EGTTR during the 2023-2030 period.

Table 1—Planned Munitions for 53 WEG Air-to-Surface Missions in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Destination scenario

Annual

quantity

Live Munitions:

Rocket

9.1 (4.1)

Surface

Missile

240.26 (108.9)

Surface

Missile

240.26 (108.9)

Surface

Missile

240.26 (108.9)

Surface

Missile

150 (68)

Surface

Missile

145 (65.7)

Surface

Missile

150 (68)

Surface

Missile

145 (65.7)

Surface

Missile

150 (68)

Surface

Missile

29.1 (13.2)

Surface

Missile

29.94 (13.6)

Surface

Missile

27.41 (12.4)

Surface

Missile

27.38 (12.4)

Surface

Missile

20.16 (9.1)

Surface

Bomb

108.6 (49.5)

HOB

Bomb

0.34(0.1)

HOB/Surface

Bomb

0.39(0.1)

Surface

Missile

0.70 (0.31)

Surface

Missile

0.70 (0.31)

Surface

Missile

0.70(0.31)

Surface

Missile

0.70(0.31)

Surface

Missile

27.47(12.5)

Surface

Bomb

6.88 (3.1)

Surface

Bomb

6.88 (3.1)

Surface

Missile

8.14 (3.7)

Surface

Bomb

193 (87.5)

Surface

Bomb

193

Surface

Gun Ammunition

4.7

Surface

100

Inert Munitions:

Missile

N/A

Missile

N/A

Missile

N/A

Missile

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

Gun Ammunition

0.09 (0.04)

N/A

16,000

Gun Ammunition

N/A

16,000

Gun Ammunition

N/A

16,000

Decoy System

N/A

Warhead replaced by FTS/Tactical Missile (TM). Identified NEW is for the FTS.

EGTTR = Eglin Gulf Test and Training Range.

The 53 WEG also conducts live air-to-air missile testing in the EGTTR. These missions also include firing inert gun ammunition and releasing flares and chaff from aircraft. Air-to-air missile testing during these missions specifically involves firing live missiles at sub-and full-scale Aerial Targets to evaluate the effectiveness of missile delivery techniques. These missions involve the use of several types of fighter aircraft. Table 2 presents information on the munitions planned to be used during 53 WEG missions in the EGTTR.

Table 2—Planned Munitions for 53 WEG Air-to-Air Missions in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Live Munitions:

Missile

113.05 (51.3)

HOB

Missile

113.05 (51.3)

HOB

Missile

113.05 (51.3)

HOB

Missile

102.65 (46.5)

HOB

Missile

117.94 (63.5)

HOB/Surface

Missile

102.65 (46.5)

HOB

Missile

60.25 (27.3)

HOB

Missile

67.9 (30.8)

HOB/Surface

Missile

60.25 (27.3)

HOB

Missile

60.55 (27.3)

HOB

Inert Munitions:

Missile

N/A

Gun Ammunition

N/A

80,000

Gun Ammunition

N/A

6,000

Flare

N/A

1,800

Chaff

N/A

6,000

Chaff

N/A

1,500

EGTTR = Eglin Gulf Test and Training Range; HOB = height of burst; lb = pound(s); mm = millimeter(s); N/A = not applicable.

Air Force Special Operations Command Training

The Air Force Special Operations Command (AFSOC) plans to continue conducting training missions during the 2023-2030 period. These missions primarily involve air-to-surface gunnery, bomb, and missile exercises. Gunnery training in the EGTTR involves firing live rounds from AC-130 gunships at targets on the water surface. Gun ammunition used for this training primarily includes 30-millimeter (mm) High Explosive (HE) and 105 mm HE rounds. A standard 105 mm HE round has a NEW of 4.7 lb. The Training Round (TR) variant of the 105 mm HE round, which has a NEW of 0.35 lb, is used by AFSOC for nighttime missions. This TR was developed to have less explosive material to minimize potential impacts to protected marine species, which could not be adequately surveyed at night by earlier aircraft instrumentation. Since the development of the 105 mm HE TR, AC-130s have been equipped with low-light electro-optical and infrared sensor systems that provide excellent night vision. Targets used for AC-130 gunnery training include Mark (Mk)-25 marine markers and inflatable targets. During each gunnery training mission, gun firing can last up to 90 minutes but typically lasts approximately 30 minutes. Live firing is continuous, with pauses usually lasting well under 1 minute and rarely up to 5 minutes. Table 3 presents information on the rounds planned for AC-130 gunnery training by AFSOC.

Table 3—Planned Rounds for AC-130 Gunnery Training in the EGTTR

Net explosive weight

(lb)/(kg)

Detonation scenario

Number of

missions

Rounds per

mission

Annual

quantity

Daytime Missions:

4.7 (2.1)

Surface

750

0.1 (0.04)

500

12,500

Nighttime Missions:

0.35 (0.2)

Surface

1,350

0.1 (0.04)

500

22,500

Total

37,100

EGTTR = Eglin Gulf Test and Training Range.

The 8th Special Operations Squadron (8 SOS) under AFSOC conducts training in the EGTTR using the tiltrotor CV-22 Osprey. This training involves firing .50 caliber rounds from CV-22s at floating marker targets on the water surface. The .50 caliber rounds do not contain explosive material and, therefore, do not detonate. Flight procedures for CV-22 training are similar to those described for AC-130 gunnery training, except that CV-22 aircraft typically operate at much lower altitudes (100 to 1,000 feet (30.48 to 304.8 m) (AGL) than AC-130 gunships (6,000 to 20,000 feet (1,828 to6,96 m) AGL). Like AC-130 gunships, CV-22s are equipped with highly sophisticated electro-optical and infrared sensor systems that allow advanced detection capability during day and night. Table 4 presents information on the rounds planned for CV-22 training missions.

Table 4—Planned Rounds for CV-22 Training in the EGTTR

Net explosive weight

(lb)

Detonation scenario

Number of

missions

Rounds per

mission

Annual

quantity

Daytime Missions:

N/A

Surface

600

15,000

Nighttime Missions:

N/A

Surface

600

15,000

Total

30,000

In addition to AC-130 gunnery and CV-22 training, AFSOC also conducts other air-to-surface training in the EGTTR using various types of live and inert bombs and missiles as shown in Table 5. These munitions are launched from various types of aircraft against small target boats, and they either detonate on impact with the target or at a programmed HOB.

Table 5—Planned Munitions for AFSOC Bomb and Missile Training in the EGTTR

Category

Net explosive

weight

(lb) (kg)

Detonation scenario

Annual

quantity

Live Munitions:

Missile

4.58 (2.1)

HOB

100

Missile

20.0 (9.07)

HOB

Rocket

2.3 (1.0)

Surface

400

Bomb

198.0 (89.8)/298.0 (135.1)

Surface

Bomb

151.0 (98.4)

Surface

Bomb

37.0 (16.7)

HOB

Bomb

36.0 (16.3)

HOB

Inert Munitions:

Gun Ammunition

N/A

30,000

Bomb

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

AFSOC = Air Force Special Operations Command; height of burst; lb = pound(s); Mk = Mark; N/A = not applicable.

96th Operations Group

Three units under the 96th Operations Group (96 OG) plan to conduct missions in the EGTTR during the 2023-2030 period: the 417th Flight Test Squadron (417 FLTS), the 96th Operational Support Squadron (96 OSS), and the 780th Test Squadron (780 TS).

The 417 FLTS plans to continue conducting AC-130 systems and munitions testing in the EGTTR. AC-130 gunnery testing is generally similar to activities previously described for AFSOC AC-130 gunnery training.

Table 6 presents information on the munitions planned for AC-130 testing in the EGTTR during the 2023-2030 mission period.

Table 6—Planned Rounds for AC-130 Gunnery Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Live Munitions:

Missile

4.58 (2.1)

Surface

Missile

20.0 (9.1)

Surface

Bomb

37.0 (16.8)

Surface

Bomb

37.0 (16.8)

Surface

Gun Ammunition

4.7 (2.1)

Surface

Gun Ammunition

0.35 (0.2)

Surface

Gun Ammunition

0.1 (0.1)

Surface

EGTTR = Eglin Gulf Test and Training Range.

The 96 OSS plans to conduct air-to-surface testing in the EGTTR using assorted live missiles and live and inert precision-guided bombs to support testing requirements for multiple programs. The planned munitions would include captive carry and munitions employment tests. During munition employment tests, the planned munitions would be launched from aircraft at various types of static and moving targets on the water surface. Table 7 presents information on the munitions planned by the 96 OSS for testing in the EGTTR.

Table 7—Planned Munitions for 95 OSS Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Live Munitions:

Missile

20.0 (9.1)

Surface

Missile

7.9 (3.6)

HOB

Bomb

37.0 (16.8)

Surface

Inert Munitions:

Bomb

N/A

Bomb

N/A

Bomb

N/A

EGTTR = Eglin Gulf Test and Training Range.

The 780 TS, the Air Force Life Cycle Management Center, and the U.S. Navy jointly conduct some test missions in the EGTTR. These missions use precision-guided bombs. Some munitions would detonate at a HOB of approximately 5 ft (0.30 m); however, these detonations are assumed to occur at the surface for the impact analysis. Other munitions would detonate either at a HOB of approximately 7 to 14 ft (2.1 to 4.2 m) or upon impact with the target (surface). For simultaneous munition launches, two munitions would be launched from the same aircraft at approximately the same time to strike the same target. These simultaneously launched munitions would strike the target within approximately 5 seconds or less of each other. Such detonations would be considered a single event, with the associated NEW being doubled for a conservative impact analysis.

Two types of targets are typically used for 780 TS tests: Container Express (CONEX) targets and hopper barge targets. CONEX targets typically consist of up to five CONEX containers strapped, braced, and welded together to form a single structure. A hopper barge is a common type of barge that cannot move itself; a typical hopper barge measures approximately 30 ft (9.1 m) by 12 ft (3.6 m) by 125 ft (38.1 m).

Other 780 TS tests in the EGTTR during the 2023-2030 mission period may include operational testing of a third bomb munition. These tests may involve live and inert testing of the munition against target boats.

Table 8 presents information on the munitions planned for these 780 TS missions in the EGTTR during the 2023-2030 period.

Table 8—Planned Munitions for Precision Strike Weapon Missions

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Live Munitions:

Missile

240.26 (108.9)

Surface

Bomb

37.0 (16.8)

HOB/Surface

Bomb

74.0 (33.35)

HOB/Surface

Bomb

22.84 (10.4)

HOB/Surface

Inert Munitions:

Missile

N/A

Bomb

N/A

Bomb

N/A

Bomb

N/A

NEW is doubled for simultaneous launch.

EGTTR = Eglin Gulf Test and Training Range; lb = pound(s); N/A = not applicable.

The 780 TS, along with the Air Force Life Cycle Management Center and U.S. Navy, plans to jointly conduct air-to-air missile testing in the EGTTR. These missions would involve the use of missiles; all missiles used in these tests would be inert. Table 9 presents information on the munitions planned for air-to-air missile testing missions in the EGTTR during the 2023-2030 mission period.

Table 9—Planned Munitions for 780 TS Air-to-Air Missile Testing in the EGTTR

Category

Net explosive weight

(lb)

Detonation scenario

Annual

quantity

Missile

N/A

Missile

N/A

Missile

N/A

EGTTR = Eglin Gulf Test and Training Range; lb = pound(s); N/A = not applicable.

The 780 TS plans to test the ability of other missiles to track and impact moving target boats in the EGTTR as shown in Table 10. The test targets would be remotely controlled boats, including the 25-foot High-Speed Maneuverable Surface Target (HSMST) (foam filled) and 41-foot (12.5 m) Coast Guard Utility Boat (metal hull).

Table 10—Planned Munitions for 780 TS Other Missile Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Missile

35.95 (16.3)

HOB

Missile

27.47 (11.1)

HOB

EGTTR = Eglin Gulf Test and Training Range; HOB = height of burst; lb = pound(s).

The 780 TS plans to test an air-to-surface tactical missile system against static and moving target boats in the EGTTR. These missiles shown in Table 11 would target foam-filled fiberglass boats approximately 25 ft (7.62 m) in length that are either anchored or towed by a remotely controlled (HSMST).

Table 11—Planned Munitions for 780 TS Other Missile Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Missile

34.08 (14.5)

Surface

The 780 TS plans to conduct surface-to-air testing of missiles in the EGTTR. These missiles are expected to be fired from the A-15 launch site on Santa Rosa Island in the EGTTR. Detailed operational data for this testing are not yet available. Standard inventory missiles would be used and up to eight tests of one type and two tests of another type per year are planned as shown in Table 12.

Table 12—Planned Munitions for 780 TS Surface-to-Air Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Missile

145.0 (65.7)

N/A (drone target)

Missile

145.0 (65.7)

N/A (drone target)

Assumed for impact analysis.

Hypersonic weapons are capable of traveling at least five times the speed of sound, referred to as Mach 5. While conventional weapons typically rely on explosive warheads to inflict damage on a target, hypersonic weapons typically rely on kinetic energy from high-velocity impact to inflict damage on targets. For the purpose of assessing impacts, the kinetic energy of a hypersonic weapon may be correlated to energy release in units of feet-lb or trinitrotoluene (TNT) equivalency.

The 780 TS supports hypersonic weapon programs which are presented in Table 13.

780 TS plans to conduct testing of one type of hypersonic missile, which would involve air launches through a north-south corridor within the EGTTR to a target location on the water surface. The dimensions and orientation of the test flight corridor within the EGTTR for these tests are to be determined; the flight corridor is expected to be 300 to 400 nmi (555 to 740 km) in total length. Live types of missiles would be fired from the southern portion of the EGTTR into either the existing LIA or planned East LIA. Up to two live of these live missiles per year are planned to be tested in the EGTTR during the 2023-2030 mission period.

The 780 TS in coordination with the U.S. Army plans to conduct testing of another type of hypersonic missile in the EGTTR. Some testing of these missiles is expected to involve surface launches from the A-15 launch site on Santa Rosa Island. The dimensions and orientation of the test flight corridor within the EGTTR for these tests are to be determined; the flight corridor is expected to be 162 to 270 nmi (300 to 500 km) in total length. For tests that involve a live warhead on these missiles, they would be preset to detonate at a specific height above the water surface (HOB/airburst) and could occur in any portion of the EGTTR. Any surface strikes planned with these live missiles would be required to be in the existing LIA or East LIA. Like inert of the previously mentioned missile type, inerts of this type could occur in any portion of the EGTTR, except between the 100-m and 400-m isobaths to prevent impacts to the Rice's whale.

Table 13—Planned Munitions for 780 TS Hypersonic Weapon Testing in the EGTTR

Category

Net explosive

weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Live Munitions:

Hypersonic Weapon

350 (158.7)

Surface

Hypersonic Weapon

46 (158.7)

HOB

Inert Munitions:

Hypersonic Weapon

N/A

Net explosive weight at impact/detonation.

The 780 TS, in coordination with the Air Force Research Laboratory, plans to conduct sink at-sea live-fire training exercises (SINKEX) testing in the EGTTR. SINKEX exercises would involve the sinking of vessels, typically 200-400 ft (61-122 m) in length, in the existing LIA. The types of munitions that would be used for SINKEX testing is controlled information and, therefore, not identified (Table 14).

Table 14—Planned 780 TS SINKEX Exercises in the EGTTR

Type

Category

Net explosive weight

(lb)

Detonation scenario

Annual

quantity

SINKEX

Vessel Sinking Exercise

Not Available

The 780 TS plans to lead or support other types of testing in the EGTTR as shown in Table 15. These missions would primarily include testing live and inert munitions against targets on the water surface, such as boats and barges. Some of the tests would involve munitions with NEWs of up to 945 lb, which is the highest NEW associated with the munitions analyzed in this LOA application

Table 15—Planned Munitions for Other 780 Test Squadron Testing in the EGTTR

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Target type

Annual

quantity

Live Munitions:

Bomb

945 (428.5)

Subsurface

TBD

4 to 8

Bomb

945 (428.5) or less

HOB

TBD

Bomb

0.4 (0.2)

HOB/Surface

Small Boat

Bomb

0.4 (0.2)

HOB/Surface

Small Boat

Inert Munitions:

Missile

N/A

TBD

Booster

N/A

TBD

Bomb

N/A

Water Surface and Barge

Torpedo

N/A

Water Surface

EGTTR = Eglin Gulf Test and Training Range; HOB = height of burst; lb = pound; (N/A = not applicable; TBD = to be determined.

The 96 OG plans to continue expanding approximately nine inert bombs a year in the EGTTR for testing purposes. The bombs are expected to be up to 2,000 lb (907 kg) in total weight. For the impact analysis, the bombs to be used by the 96 OG in the EGTTR during the 2023-2030 mission period are assumed to be 2,000 lb (907 kg) General Purpose (GP) inert bombs (Table 16).

Table 16—Planned Munitions for Other 96 OG Inert Bomb Testing in the EGTTR

Category

Net explosive weight

(lb)

Detonation scenario

Annual

quantity

Bomb

N/A

Assumed for impact analysis.

EGTTR = Eglin Gulf Test and Training Range; N/A = not applicable.

Naval School Explosive Ordnance Disposal (NAVSCOLEOD)

NAVSCOLEOD plans to conduct training missions in the EGTTR which would include Countermeasures (MCM) exercises to teach NAVSCOLEOD students techniques for neutralizing mines underwater (Table 17). Underwater MCM training exercises are conducted in nearshore waters and primarily involve diving and placing small explosive charges adjacent to inert mines by hand; the detonation of such charges disables live mines. NAVSCOLEOD training is conducted offshore of Santa Rosa Island and in other locations and has not yet extended into the EGTTR. NAVSCOLEOD training planned for the 2023-2030 mission period would extend approximately 5 nmi (9.26 km) offshore of Santa Rosa Island, in the EGTTR. Up to 8 MCM training missions would be conducted annually in the EGTTR during the 2023-2030 period. Each mission would involve 4 underwater detonations of charges hand placed adjacent to inert mines, for a total of 32 annual detonations. The MCM neutralization charges consist of C-4 explosives, detonation cord, non-electric blasting caps, time fuzes, and fuze igniters; each charge has a NEW of approximately 20 lb. (9.07 kg). During each mission, with a maximum of 4 charges, would detonate with a delay no greater than 20 minutes between shots. After the final detonation, or a delay greater than 20 minutes, a 30-minute environmental observation would be conducted. Additionally, NAVSCOLEOD plans to conduct up to 80 floating mine training missions, which would involve detonations of charges on the water surface; these charges would have a NEW of approximately 5 lb (2.3 kg). All NAVSCOLEOD missions would occur only during daylight hours.

Table 17—Planned Munitions for NAVSCOLEOD Training in the EGTTR

Type

Category

Net explosive weight

(lb)/(kg)

Detonation scenario

Annual

quantity

Underwater Mine Charge

Charge

20 (9.1)

Subsurface

Floating Mine Charge

Charge

5 (2.3)

Surface

Estimated.

Description of Stressors

The USAF uses the EGTTR for training purposes and for testing of a variety of weapon systems described in this planned rule. All of the weapons systems considered likely to cause the take of marine mammals involve explosive detonations. Training and testing with these systems may introduce acoustic (sound) energy or shock waves from explosives into the environment. The following section describes explosives detonated at or just below the surface of the water within the EGTTR. Because of the complexity of analyzing sound propagation in the ocean environment, the USAF relied on acoustic models in its environmental analyses and rulemaking/LOA application that considered sound source characteristics and conditions across the EGTTR.

Explosive detonations at the water surface send a shock wave and sound energy through the water and can release gaseous by-products, create an oscillating bubble, or cause a plume of water to shoot up from the water surface. When an air-to-surface munition impacts the water, some of the kinetic energy displaces water in the formation of an impact “crater” in the water, some of the kinetic energy is transmitted from the impact point as underwater acoustic energy in a pressure impulse, and the remaining kinetic energy is retained by the munition continuing to move through the water. Following impact, the warhead of a live munition detonates at or slightly below the water surface. The warhead detonation converts explosive material into gas, further displacing water through the rapid creation of a gas bubble in the water, and creates a much larger pressure wave than the pressure wave created by the impact. These impulse pressure waves radiate from the impact point at the speed of sound in water, roughly 1,500 m per second. If the detonation is sufficiently deep, the gas bubble goes through a series of expansions and contractions, with each cycle being of successively lower energy. When detonations occur below but near the water surface, the initial gas bubble reaches the surface and causes venting, which also dissipates energy through the ejection of water and release of detonation gasses into the atmosphere. When a detonation occurs below the water surface after the impact crater has fully or partially closed, water can be violently ejected upward by the pressure impulse and through venting of the gas bubble formed by the detonation.

With radii of up to 15 m, the gas bubbles that would be generated by EGTTR munition detonations would be larger than the depth of detonation but much smaller than the water depth, so all munitions analyzed are considered to fully vent to the surface without forming underwater bubble expansion and contraction cycles. When detonations occur at the water surface,

a large portion of the energy and gasses that would otherwise form a detonation bubble are reflected upward from the water. Likewise, when a shallow detonation occurs below the water surface but prior to the impact crater closing, considerable energy is reflected upward from the water. As a conservative assumption, no energy losses from surface effects are included in the acoustic model.

The impulsive pressure waves generated by munition impact and warhead detonation radiate spherically and are reflected between the water surface and the sea bottom. There is generally some attenuation of the pressure waves by the sea bottom but relatively little attenuation of the pressure waves by the water surface. As a conservative assumption, the water surface is assumed to be flat (no waves) to allow for maximum reflectivity. Additionally, is it assumed that all detonations occur in the water and none of the detonations occur above the water surface when a munition impacts a target. This conservative assumption implies that all munition energy is imparted to the water rather than the intended targets. The potential impacts of exposure to explosive detonations are discussed in detail in the Potential Effects of Specified Activities on Marine Mammals and their Habitat section of the notice of proposed rulemaking published in the

Federal Register

(88 FR 8146; February 7, 2023).

Comments and Responses

We published the proposed rule in the

Federal Register

on February 7, 2023 (88 FR 8146), with a 30-day comment period. With that proposed rule, we requested public input on our analyses, our preliminary findings, and the proposed regulations, and requested that interested persons submit relevant information and comments. During the 30-day comment period, we received 10 comment submissions: one from the Marine Mammal Commission (Commission) and nine from private citizens. NMFS has reviewed and considered all public comments received on the proposed rule and issuance of the LOA. The private citizens' comments generally expressed disapproval of the action due to perceived potential impact to the Endangered Species Act (ESA)-listed Rice's whale. Our responses to all comments that are pertinent to this action are described below.

Comment 1:

The Commission wrote that the proposed rule implied that behavioral takes were not estimated for exercises that included only one detonation per day. NMFS had noted that the potential for behavioral response from a single detonation was quantitatively accounted for by using the temporary threshold shift (TTS) threshold. Since the Commission believes that behavioral takes should be authorized for activities involving single detonations, it recommended that NMFS authorize the Level B harassment behavior takes of marine mammals, in addition to TTS takes, for mission-day categories J and K in the final rule or any LOA issued thereunder and ensure that the preamble to the final rule is clear regarding the fact that behavior takes were authorized for single-detonation missions.

Response:

NMFS inadvertently conveyed in the proposed rule that the potential for behavioral response for single detonations was accounted for within the TTS thresholds/takes (5 dB sound exposure level (SEL) less than the TTS threshold), which is how NMFS typically recommends considering behavioral harassment from single detonations. However, the USAF computed behavioral threshold distances and takes for Missions J and K (both single detonation) using the underwater acoustic model. These model runs were done specifically to estimate behavioral effects, just like other model runs were done to estimate SEL-based TTS and PTS. Behavioral takes were actually estimated based on the species density within the area exposed to sound levels from 170 dB SEL to 165 dB SEL, where 170 dB SEL represents the TTS threshold. This language has been revised and clarified in the preamble to this final rule. As a general matter, NMFS continues to find that take by behavioral harassment from single explosive detonations is unlikely to result from exposures below the TTS threshold; however, at Eglin Air Force Base's request, we have authorized these takes to provide coverage in the unlikely event they should occur.

Comment 2:

The Commission notes that to minimize impacts on Rice's whales, NMFS has prohibited the use of live-fire munitions between the 100- and 400-m isobaths in the existing and new live impact areas (LIAs) and seaward of the setbacks from the 100-m isobath. The Commission recommended that NMFS prohibit use of live-fire munitions in the existing and new LIAs both within the core distribution area (CDA) and seaward of the setbacks from shallowest depths of the CDA.

Response:

Within the LIAs, the CDA boundaries are comprised of straight lines that generally track along the 100-meter isobath boundary. The isobath is not a straight line but meanders back and forth across the CDA boundary. In some areas, the CDA boundary traverses areas of less depth than the 100-m isobath. Rice's whale densities are extremely low at the 100-meter isobath boundary and would be statistically meaningless in shallower waters (also no Rice's whale or other baleanopterid has been sighted by NMFS' aerial surveys in waters less than 100-m depth in this area, despite extensive coverage out to the 200-m isobath). The setbacks from the 100-meter isobath range from 7.323 km (mission-day A) to 0.368 km (mission-day R) landward. In some portions of both LIAs, the shallowest boundary of the CDA covers an area that is greater than the given setback distance landward of the 100-meter isobath. Therefore, using the CDA boundary would result in additional loss of LIA area for USAF, based on the CDA boundary itself, which is landward of some of the current setbacks and based on any new setbacks from the CDA boundary, most of which would be greater than the current setbacks. Currently, there are no other suitable locations to conduct live missions in the EGTTR outside the existing LIA and proposed East LIA. USAF has given up significant amounts of area within each LIA to reduce potential Level B harassment to the Rice's whale to the lowest levels practicable. These setbacks impact all USAF EGTTR missions. Any additional loss of LIA would not be practicable as it would have a negative disproportionate impact on the ability of the USAF to conduct missions and on national security preparedness. Further, as indicated, such an additional setback would provide little, if any, additional reduction of impacts to Rice's whales and, accordingly, NMFS has not included this recommendation.

Comment 3:

The Commission does not believe that the USAF would be able to visually monitor effectively for marine mammals entering the mortality and injury zones, particularly during the time between when the smaller mission area has been cleared during pre-mission surveys with vessels exiting beyond the larger human safety zone (up to 13 nmi/24 km) and the time of detonation(s) which would be a minimum of 30 minutes. The Commission also notes that the USAF video cameras available to assist with visual monitoring are not always used or operational when intended to be used. The Commission also noted that due to high altitudes of aircraft used during aerial surveillance, effective monitoring is not possible.

Response:

NMFS disagrees with the Commission's assertions for several reasons. The 24 km (12.9 nmi) distance is for the largest, and less frequent, net-

explosive weight (NEW) mission days when the detonation would be 945 lbs. This would occur on a maximum of 10 days per year. The Commission fails to note that the number of vessels employed would be proportionate to the size of the NEW used on a given mission. Up to 25 vessels would be used on days when the largest NEWs are planned. Further, the vessels will continue to monitor for marine mammals in or approaching the smaller mitigation zone both as they move outward towards the human safety zone, and from the edge of the human safety zone—if the mission area/mitigation zone is clear when they move out to the human safety zone, it is unlikely that a marine mammal would pass by the monitors to the inner mitigation zone in the next 30 minutes without being seen.

NMFS notes that video cameras are planned/required for use in all regular situations, and might not be used in situations of unplanned circumstances, such as in cases of equipment malfunction. In such situations, the test engineer and other staff can make a decision to delay, cancel, or postpone a mission due to asset status (

i.e.,

if video cameras are also unavailable or malfunctioning).

Regarding the effectiveness of aerial monitoring, NMFS notes that the electro-optical sensors employed by the USAF were specifically designed to detect targets on the electromagnetic spectrum under such areal and altitudinal parameters. NMFS is confident in the USAF's ability to effectively monitor for marine mammals from aircraft and marine vessels.

Comment 4:

The Commission has previously recommended that the USAF's mitigation measures be supplemented with passive acoustic monitoring (PAM). As part of the previous 2018 rulemaking and issued LOA, NMFS required the USAF to: (1) conduct a PAM study as an initial step toward understanding acoustic impacts of underwater detonations, if funding was approved, and (2) conduct a follow-up PAM study to investigate marine mammal vocalizations before, during and after live missions in the EGTTR. The Commission recommended as part of this final rule that NMFS require the USAF to prioritize (1) completing both aspects of its PAM study and (2) further investigate ways to supplement its mitigation measures with the use of real-time PAM devices (

i.e.,

sonobuoys or hydrophones) in any final rule issued, similar to the previous final rule.

Response:

The USAF conducted a single PAM study (Leidos 2020) on underwater detonations which was the first of the two-part condition of the 2018-2023 LOA. The study determined that inert underwater detonations were generally louder than expected. As a result of these findings, the USAF included analyses of impacts of inert munitions in the LOA application and NMFS is requiring appropriate mitigation measures for inert munitions.

As of this writing, funding has been requested from near-term funding sources but has not yet been approved by the USAF for the second part of the study, which was to follow up on the results of the initial PAM study. NMFS and the USAF have reviewed the findings from the initial study and will discuss specific next steps. Furthermore, NMFS has included language in this final rule and the LOA requiring the USAF to prioritize studies to (1) follow up on the results of the initial PAM study by investigating marine mammal vocalizations before, during, and after live missions in the EGTTR, pending the availability of funding; and (2) investigate ways to supplement its mitigation measures with the use of real-time PAM devices, pending the availability of funding.

The Commission recommended that NMFS and the USAF investigate the possible use of sonobuoys for the second part of the study. NMFS and the USAF appreciate the Commission's recommendations regarding possible use of various types of sonobuoys.

Comment 5:

The Commission recommended that NMFS require the USAF to implement mitigation measures for SINKEX activities that are similar to those required by NMFS for incidental take regulations for the U.S. Navy.

Response:

Below, NMFS addresses each of the specific mitigation measures recommended by the Commission (

i.e.,

mitigation measures for SINKEX activities that are similar to those required by NMFS for U.S. Navy incidental take regulations.

(1) The Commission recommended that the USAF establish two platforms (aerial and vessel) for conducting visual monitoring of a 4.6-km mitigation zone from 90 minutes before the first firing.

NMFS will require all range clearing vessels to be on site 90 minutes before the mission to clear the prescribed human safety zone and survey the mitigation zone for the given mission-day category. Up to 25 vessels will be used depending upon the size of the NEW. Not all of these vessels will contain PSOs, but these will also be looking for marine mammals in addition to range-clearing exercises. PSOs will be stationed on all vessels that are required to monitor the mitigation zones for the given mission-day category for a minimum of 30 minutes or until the entirety of the mitigation zone has been surveyed, whichever takes longer. Furthermore, all mission-day categories require aerial-based monitoring, assuming assets are available and when such monitoring does not interfere with testing and training parameters required by mission proponents.

While the aerial platforms may not always be onsite 90 minutes before the mission, the measures required in these regulations provide similar equivalent protection, as the entirety of the mitigation zone will have been monitored by PSOs on vessels and aircraft a short time before the mission commences.

(2) The Commission recommended that the USAF should conduct both visual monitoring from a vessel and passive acoustic monitoring of the mitigation zone during the exercise.

Real-time visual monitoring from a vessel would pose a safety threat to both the PSO as well as crew of the vessel. All vessels must have exited the human safety zone prior to the commencement of SINKEX activities. The large size of the human safety zone means that extended distance from a vessel to the SINKEX target area would not allow for effective monitoring from a vessel. However, video-based monitoring will be employed during SINKEX missions, which provides real-time observation data for the mitigation zone.

NMFS has engaged in multiple discussions with the USAF about the implementation of PAM. However, human safety concerns and the inability to make mission go/no-go decisions in a timely manner are the most immediate obstacles for the USAF implementing PAM as part of the suite of mitigation measures during live weapon missions in the EGTTR. For safety purposes during live air-to-surface missions in the EGTTR and during SINKEX exercises portions of the Gulf of Mexico are closed off to human activity. The human safety zone corresponds to the weapon safety footprint. The size of the closure area varies depending on the weapons being dropped, the type of aircraft being used, and the specific release parameters (direction, altitude, airspeed, etc.) requested by the mission group, but it always encompasses the area occupied by the instrumentation barge (GRATV). Typically, this footprint is where personnel are restricted to ranges between a 9-nautical mile (nmi) radius up to a 12-nmi radius around the GRATV from the target and the GRATV that is usually within hundreds of meters of the target. As part of PAM, biologists generally deploy an array of hydrophones, listen for vocalizations

from a nearby boat, and use software to triangulate an animal's general location. The ability to execute this requires multiple hydrophones lined up in a carefully determined array or fence configuration with a trained biologist in close proximity to the hydrophones. Alternatively, the biologist could be stationed in a remote location but would require a direct line-of-sight for radio links to transmit the data from the hydrophones. The maximum distance that a remote link could be established is estimated to be about 5 nmi. This would fall inside the human safety zone. Therefore, real-time monitoring for marine mammal vocalizations during a SINKEX mission is not considered feasible for human safety concerns.

The USAF is supportive of PAM and has conducted a NMFS-approved PAM study in 2020 to increase our understanding of acoustic impacts associated with underwater detonations. Given the need for additional research as recommended by the Commission, additional studies have been established as conditions of these regulations and LOA. Development, testing and full implementation of a real-time PAM system is not likely feasible during the effective period of the new LOA due to human safety concerns and the need for additional investigations of efficacious protocols. Considering all of this, the use of PAM as a real-time mitigation measure is not practicable at this time.

(3) The Commission recommended that the USAF observe marine mammals in the vicinity of where detonations occurred for 2 hr after sinking the vessel or until sunset (whichever comes first).

The post-mission survey area will be the area covered in 30 minutes of observation by both aerial crews and vessels in a direction down-current from the impact site or the actual pre-mission survey area, whichever is reached first. PSOs must survey the mission site for any dead or injured marine mammals. Additionally, post-mission cleanup operations will recover as much target-related debris as possible from the water surface by hand and by using dip nets. The USAF reports that typical post-cleanup operations involve the use of up to 10 vessels for up to 2 to 3 hours depending on the size of the NEW, and personnel on these vessels will be instructed to report any dead or injured marine mammals to the Lead Biologist. NMFS is not requiring a minimum time limit or specifying the number of vessels that must be employed post mission since it is difficult, if not impossible, to predict how much debris will occur at or near a given SINKEX mission location. Furthermore, it is inefficient and costly to require multiple vessels primarily engaged in cleanup activities to continue monitoring for extended periods after cleanup is complete. For single-detonation SINKEX actions, the USAF has committed to survey the entirety of the mission area or survey for 30 minutes, whichever comes first.

(4) The Commission recommended that any additional platforms supporting the primary mission activity (

e.g.,

providing range clearance) must assist in visual observation of the area where detonations occurred.

As noted above, up to 10 USAF support vessels primarily focused on collecting debris will spend several hours in the mission area collecting debris from damaged targets. All vessels will be instructed to report any dead or injured marine mammals to the Lead Biologist.

In summary, with the exception of PAM, which NMFS concurs with the USAF is not practicable at this time, the USAF's required mitigation and monitoring measures are either similar to those employed by the Navy or provide comparable protection. Further, as noted, a requirement to investigate ways to supplement the USAF's mitigation measures with the use of real-time PAM devices has been included in these regulations. Monitoring reports under the LOA effective from 2018 through 2021 have not recorded take of any marine mammals. Only bottlenose dolphins have been observed and there have not been sightings of whales of any species. Based on the information above, NMFS has determined that the mandated mitigation and monitoring measures required for SINKEX activities in the EGTTR effect the least practicable adverse impact on the affected species and their habitat. Therefore, NMFS is not adopting the Commission's recommendation that the USAF measures be changed to mirror the Navy's protocols.

Comment 6:

Several commenters wrote that the USAF should not be permitted to take marine mammals in the EGTTR since they are protected by the Marine Mammal Protection act and the Endangered Species Act; therefore, all activities that may harm the species are required to be banned.

Response:

Both the MMPA and the ESA allow for the take of marine mammals or ESA-listed species, respectively, provided certain findings are made. Further, the MMPA states that NMFS “shall issue” incidental take authorizations provided the necessary findings are made. As described in this final rule, NMFS' analysis supports our determination that the authorized takes will have a negligible impact on the affected species or stocks. Further, we have included required mitigation measures that ensure that the testing and training activities in the EGTTR will have the least practicable adverse impact on affected marine mammal species or stocks.

Comment 7:

One commenter wrote that the activities proposed by the USAF in the EGTTR would exacerbate threats to the Rice's whale, leading the species to its eventual demise. Therefore, NMFS is unable to make a negligible impact determination regarding the species. As such, the requested incidental take should not be authorized. A separate commenter wrote that changes in marine mammal behavior have been found to directly impact health, including immunological changes in marine mammals, making individuals more susceptible to infection and making populations more susceptible to disease exposure. The commenter stated that this level of impact could have serious repercussions for the species as a whole and cannot be considered negligible.

Response:

There is no evidence to support the statement that the USAF's planned activities in the EGTTR would lead to the extinction of the species. As indicated in our analysis and by the authorization of a low number of takes by Level B harassment (no more than 6 in any year), NMFS acknowledges that some level of impact, in the form of behavioral disturbance, is likely to occur in the Rice's whale. However, as required to allow for incidental take, we further determined that such impacts resulting from the specified activity are not reasonably expected to, or not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival (

i.e.,

population-level effects). As discussed in the proposed rule and this final rule, NMFS made a negligible impact determination. Since NMFS did arrive at a negligible impact determination and satisfied the MMPA requirements, there are no legal grounds for prohibiting authorized take.

Comment 8:

One commenter wrote that testing explosives in the EGTTR could affect marine mammals even if they are not present since sources of food could be disturbed for the mammals, changing their hunting patterns, and disrupting the ecosystem.

Response:

The Potential Effects of Specified Activities on Marine Mammals and Their Habitat section of the proposed rule (88 FR 8146, February 7, 2023) described the potential impacts of EGTTR activities on marine mammal habitat and prey sources. NMFS

acknowledges that explosive detonations can impact both fish and invertebrate prey sources in manners ranging from behavioral disturbance to mortality for animals that are very close to the source. However, as described in the analysis, these impacts are expected to be short term and localized, and would be inconsequential to the fish and invertebrate populations, and to the marine mammals that use them as prey.

Comment 9:

One commenter mistakenly wrote that the USAF anticipated take resulting from Level A and Level B harassment of Rice's whales with authorized Level A harassment of 2 Rice's whale, permanent threshold shifts (PTS) of 4 individuals, temporary threshold shifts (TTS) of 14 individuals, and behavior disturbance of 28 individuals over the 7-year analysis period (NMFS 2023). The commenter further suggested that since the species abundance is 51 individuals, the anticipated take numbers are proportionally significant, particularly when it comes to behavioral impacts, which are anticipated to affect the majority of the population (56 percent) over a seven-year period.

Response:

The commenter is incorrect regarding the number of PTS and TTS takes. NMFS has authorized 6 takes by Level B harassment per year (2 by TTS and 4 behavioral harassment). NMFS does not expect and has not authorized take of Rice's whale by Level A harassment.

Further, if one assumes that each of the 6 annual exposures is incurred by a different whale, these authorized takes affect 11.8 percent (6/51) of the population during any given year. Importantly, each of those instances of take represents exposure within 1 day of the year. This represents low magnitude, short duration impacts to a relatively small portion of the total population.

Comment 10:

One commenter wrote that the Rice's whale is highly sensitive to

any

anthropogenic forces and, therefore, authorization of the proposed activities would result in significant impacts and violate section 101 of the MMPA. They wrote that it was time for NMFS to fulfill their duty to conserve and protect this important marine resource by denying the USAF's request to take Rice's whales. Another commenter asked if it is necessary to test these weapons in the water. They stated that this represents a risk to ocean life and that there should be other options for locations to test military weapons. Another commenter asked why these military testing activities must take place where species stocks are struggling.

Response:

NMFS acknowledges the comments and refers back to the response to comment 6 above. Assuming that the requirements of the MMPA are met,

e.g.,

findings of negligible impact and least practicable adverse impact, NMFS does not have discretion as to whether it may issue incidental take regulations (ITRs) and LOAs under those ITRs and shall prescribe mitigation measures that ensure the least practicable adverse impact on marine mammals and their habitat as defined in the military readiness provisions of the MMPA.

Comment 11:

A commenter noted that the USAF entirely ignores potential impacts resulting from increased vessel traffic in Rice's whale habitat. The LOA Request details that EGTTR missions require up to 25 mission-support boats to establish a “safety zone” prior to and throughout the missions; as well as vessels for post-mission surveys and debris cleanup. For an endangered marine mammal whose primary habitat is already overlapping with high-traffic channels, the commenter wrote that recognition of the potential for vessel strikes is warranted.

Response:

NMFS has considered the number of vessels involved in the activity and the potential for vessel strike. The number of USAF vessels required for any given mission day category will vary depending on the mission-day category and the size of the NEW. The use of 25 vessels would occur infrequently when explosives with the largest NEWs would be deployed, and their entire purpose would be to detect and minimize impacts to marine mammals. Furthermore, all USAF vessels must adhere to required vessel strike avoidance measures that are expected to avoid strikes of marine mammals. Specifically, measures require vessels to stay 500 m away from any sighted Rice's whale. If a baleen whale cannot be positively identified to species level then it must be assumed to be a Rice's whale and 500 m separation distance must be maintained. Additionally, vessels must avoid transit in the Rice's whale CDA and within the 100-400 m isobath zone outside the CDA. If transit in these areas is unavoidable, vessels must not exceed 10 knots and transit at night is prohibited. The LIAs themselves overlay only a portion of the Rice's whale CDA.

No Air Force vessels have ever struck a whale in the EGTTR. Given the required vessel strike avoidance measures, the infrequency of vessel strikes more broadly, and the comparatively low numbers of vessels used in EGTTR activities, the potential for strike by a USAF vessel of any marine mammal is considered so low as to be discountable, and this is especially true for the Rice's whale, given their low density. NMFS does not anticipate, and has not authorized, vessel strike of Rice's whales or any other marine mammal.

Comment 12:

A commenter stated that the proposed regulation fails to provide for long-term environmental monitoring plans, and cleanup initiatives, in response to the contamination associated with the disposal of ordnance and target vessels in the sea. The commenter urged NMFS to expand the proposed rule to include such items. They referred to the Military Munitions Response Program, which addresses munitions-related concerns, such as environmental and health hazards from releases of unexploded ordnance (UXO) and discarded military munitions (DDM), and prioritizes sites for cleanup based on risks to the environment.

Response:

There is no evidence that USAF activities in the EGTTR result in contamination from UXOs, target vessels or any other mission-related activities. USAF post-mission cleanup procedures minimize the amount of mission-related debris that remains on the water surface and in the water column. Post-mission cleanup crews recover as much target-related debris as possible from the water surface by hand and by using dip nets; typical post-cleanup operations involve the use of several boats for up to 2 to 3 hours. Target-related debris that is not recovered by cleanup crews is dispersed by ocean currents, and much of it is expected to eventually settle on the seafloor. Based on the amount of target-related debris that would be deposited into the marine environment, post-mission cleanup of the debris, and dispersion of the unrecoverable debris by ocean currents, we conclude that any associated impacts on marine mammal habitat would be minimal.

After being deposited on the seafloor, debris items may become partially or entirely buried in sediments over time, depending on the item's size, shape, and density, and environmental factors such as sediment characteristics, water depth, and the occurrence of strong storms that may move sediments. Munitions that become buried deep in sediments may experience less corrosion because of low oxygen levels and may remain intact for longer periods of time. Inert munitions and UXO that settle on the seafloor would displace the habitat provided by the affected sediments to benthic epifauna and infauna but, like other sunken artificial structures, would also provide substrate that could be used as habitat by marine organisms. The

overall level of disturbance to marine sediments in the EGTTR from mission-related debris is expected to be minor based on the quantity of debris that would be deposited on the seafloor and the expected behavior of the debris in the marine environment over time. Based on the analysis conducted in the current EGTTR Range Environmental Assessment (REA) regarding metals, explosives, and other materials associated with EGTTR operations, USAF activities would have been unlikely to adversely impact water or sediment quality. The analyses of these potential impacts are discussed in detail in the current EGTTR REA (USAF 2022).

The MMPA requires that NMFS include marine mammal monitoring and reporting measures that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present while conducting the activities. Monitoring for EGTTR activities is described in the Monitoring section and requires PSOs to provide description of observed behaviors (in both the presence and absence of test activities), which will help us better understand the impacts of EGTTR activities on marine mammals. There are no MMPA requirements regarding wide-spread environmental or ecological monitoring beyond what has just been described. Long-term environmental monitoring and additional cleanup initiatives are beyond the scope of this action.

Comment 13:

One commenter was concerned that explosives compounds containing carcinogens and toxins can accumulate in coastal environments and marine organisms, which can cause sub-lethal genetic and metabolic effects. Furthermore, there is also a risk that chemical agents will be spread through the food chain.

Response:

See the response to comment 12 above.

Comment 14:

The commenter wrote that no critical habitat has been designated for the Rice's whale as is required under the Endangered Species Act. Therefore, NMFS should make designating critical habitat for Rice's whales a priority before approving authorizations for the USAF to participate in military activities that threaten the species' survival.

Response:

Critical habitat is defined as habitat needed to support recovery of species listed under the Endangered Species Act and NMFS Fisheries is required to determine whether there are areas that meet the definition of critical habitat. Currently, NMFS is working on an ESA rulemaking to propose designation of critical habitat for the Rice's whale which contains: (1) the biological information used to determine the specific areas containing the features essential to the conservation of the species requiring special management, and (2) consideration of the national security, economic, and other relevant impacts of designating critical habitat.

The designation of critical habitat for an ESA-listed species, in this case the Rice's whale, is a separate action and not a prerequisite to fulfilling our statutory mandate under section 101(a)(5)(A) of the MMPA.

Changes From the Proposed Rule to the Final Rule

This final rule includes no substantive changes from the proposed rule. Minor typographical errors were included in several tables in the proposed rule (

i.e.,

Tables 25, 36, and 37 in the preamble and Table 1 in the regulatory text). The values have been corrected in this final rule. The exposure analysis and take estimations in the proposed rule were based on the correct numbers so were not affected by this typographical error. They remain unchanged as part of this final rule.

The preamble text in the Pre-Mission Surveys section and § 218.64(a)(1)(iii) in the proposed rule stated that “For all live missions except gunnery missions, USAF PSOs must monitor the mitigation zones as defined in Table 2 for the given mission-day category for a minimum of 30 minutes or until the entirety of the mitigation zone has been surveyed, whichever comes first.” This has been revised in the final rule to read “. . . for a minimum of 30 minutes or until the entirety of the mitigation zone has been surveyed, whichever takes longer.” NMFS and the USAF believe that this revision ensures that the entirety of all of the mitigation zones will be monitored. NMFS revised the language in the preamble pertaining to behavioral harassment thresholds for single detonations as explained in the response to Comment 1. Finally, NMFS will require the USAF to conduct two passive acoustic monitoring (PAM) studies, pending approval of funding. These studies are described in the response to comment 4 and have been included in the regulatory text in a new paragraph (f) on acoustic monitoring within § 218.65, entitled “Requirements for monitoring and reporting”.

Description of Marine Mammals in the Area of the Specified Activities

Marine mammal species and their associated stocks that have the potential to occur in the project are presented in Table 18. The USAF anticipates the take of individuals of three marine mammal species by Level B harassment and two of those species by Level A harassment. The USAF does not request authorization for any serious injuries or mortalities of marine mammals, and NMFS agrees that serious injury and mortality is unlikely to occur from the USAF's activities.

The proposed rule included additional information about the species in this rule, all of which remains valid and applicable but has not been reprinted in this final rule, including a subsection entitled

Marine Mammal Hearing

that described the importance of sound to marine mammals and characterized the different groups of marine mammals based on their hearing sensitivity. Therefore, we refer the reader to our

Federal Register

notice of proposed rulemaking (88 FR 8146; February 7, 2023) for more information.

Information on the status, distribution, abundance, population trends, habitat, and ecology of marine mammals in the EGTTR may be found in Chapter 4 of the USAF's rulemaking/LOA application. NMFS reviewed this information and found it to be accurate and complete. All stocks managed under the MMPA in this region are assessed in NMFS' 2021 U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessment (Hayes

et al.

2022;

https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports

). All values presented in Table 18 are the most recent available at the time of publication and are available online at:

www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

Table 18—Marine Mammals Potentially Present in the Specified Geographical Region

Common name

Scientific name

Stock

ESA/MMPA status; strategic

(Y/N)

NMFS stock abundance

(CV, N

min

, most recent abundance survey)

Potential biological removal

(PBR)

Annual M/SI

Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)

Family Balaenopteridae (rorquals):

Rice's whale

Balaenoptera ricei

Gulf of Mexico (GOM)

E/D; Y

51 (0.50; 34; 2017-18)

0.1

0.5

Superfamily Odontoceti (toothed whales, dolphins, and porpoises)

Family Delphinidae:

Common bottlenose dolphin

Tursiops 36runcates truncatus

Northern GOM Continental Shelf

-; N

63,280 (0.11; 57,917; 2018)

556

Atlantic spotted dolphin

Stenella frontalis

GOM

-; N

21,506 (0.26; 17,339; 2017-18)

166

ESA status: Endangered/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.

NMFS marine mammal stock assessment reports online at:

www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

CV is coefficient of variation; N

min

is the minimum estimate of stock abundance.

These values, found in NMFS' Stock Assessment Reports (SARs), represent annual levels of human-caused mortality (M) plus serious injury (SI) from all sources combined (

e.g.,

commercial fisheries, ship strike). These values are generally considered minimums because, among other reasons, not all fisheries that could interact with a particular stock are observed and/or observer coverage is very low, and, for some stocks (such as the Atlantic spotted dolphin and continental shelf stock of bottlenose dolphin), no estimate for injury due to the

Deepwater Horizon

oil spill has been included. See SARs for further discussion.

The 2021 final rule refers to the Gulf of Mexico (GOM) Bryde's whale (

Balaenoptera edeni

). These whales were subsequently described as a new species, Rice's whale (

Balaenoptera ricei

) (Rosel

et al.,

2021).

Below, we include additional information about the marine mammals in the area of the specified activities that informs our analysis, such as identifying known areas of important habitat or behaviors, or where Unusual Mortality Events (UME) have been designated.

Rice's Whale

The Gulf of Mexico Bryde's whale was listed as endangered throughout its entire range on April 15, 2019, under the Endangered Species Act (ESA). Based on genetic analyses and new morphological information NOAA Fisheries recently revised the common and scientific names to recognize this new species (

Balaenoptera ricei

) as being separate from other Bryde's whale populations (86 FR 47022; August 21, 2021). Rosel and Wilcox (2014) first identified a new, evolutionarily distinct lineage of whale in the Gulf of Mexico. Genetic analysis of whales sampled in the northeastern Gulf of Mexico revealed that this population is evolutionarily distinct from all other whales within the Bryde's whale complex and all other known balaenopteridae species (Rosel and Wilcox 2014).

The Rice's whale is the only year-round resident baleen whale species in the Gulf of Mexico. Rosel

et al.

(2021) reported that based on a compilation of sighting and stranding data from 1992 to 2019, the primary habitat of the Rice's whale is the northeastern Gulf of Mexico, particularly the De Soto Canyon area, at water depths of 150 to 410 m.

Biologically Important Areas (BIAs) include areas of known importance for reproduction, feeding, or migration, or areas where small and resident populations are known to occur (Van Parijs, 2015). Unlike ESA critical habitat, these areas are not formally designated pursuant to any statute or law but are a compilation of the best available science intended to inform impact and mitigation analyses. In 2015, a year round small and resident population BIA for Bryde's whales (later designated as Rice's whales) was identified from the De Soto Canyon along the shelf break to the southeast (LaBrecque

et al.

2015). The 23,559 km

BIA covers waters between 100 and 300 m deep from approximately south of Pensacola to approximately west of Fort Myers, FL (LaBrecque

et al.

2015). The deepest location where a Rice's whale has been sighted is 408 m (Rosel

et al.

2021). Habitat for the Rice's whale is currently considered by NMFS to be primarily within the depth range of 100 to 400 m in this part of the Gulf of Mexico (NMFS 2016, 2020a), and in 2019 NMFS delineated a Core Distribution Area (

https://www.fisheries.noaa.gov/resource/map/rices-whale-core-distribution-area-map-gis-data

) based on visual and tag data available through 2019. No critical habitat has yet been designated for the species, and no recovery plan has yet been developed.

Unusual Mortality Events (UMEs)

An UME is defined under section 410(6) of the MMPA as a stranding that is unexpected; it involves a significant die-off of any marine mammal population and demands immediate response. There are currently no UMEs with ongoing investigations in the EGTTR. There was a UME for bottlenose dolphins that was active beginning in February 2019 and closing in November of the same year that included the northern Gulf of Mexico. Dolphins developed lesions that were thought to be caused by exposure to low salinity water stemming from extreme freshwater discharge. This UME is closed.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

We provided a detailed discussion of the potential effects of the specified activities on marine mammals and their habitat in our

Federal Register

notice of proposed rulemaking (88 FR 8146; February 7, 2023). In the Potential Effects of Specified Activities on Marine Mammals and Their Habitat section of the proposed rule, NMFS provided a description of the ways marine mammals may be affected by these activities in the form of sensory impairment (permanent and temporary threshold shift and acoustic masking), physiological responses (particularly stress responses), behavioral disturbance, or habitat effects. All of this information remains valid and applicable. Therefore, we do not reprint the information here but refer the reader to that document.

Having considered the new information, along with information

provided in public comments on the proposed rule, we have determined that there is no new information that substantively affects our analysis of potential impacts on marine mammals and their habitat that appeared in the proposed rule, all of which remains applicable and valid for our assessment of the effects of the USAF'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 is based on the maximum amount that is reasonably likely to occur, depending on the type of take and the methods used to estimate it, as described in detail below. NMFS agrees that the methods the USAF has put forth described herein to estimate take (including the model, thresholds, and density estimates), and the resulting numbers estimated for authorization, are appropriate and based on the best available science.

All takes are by harassment. For a military readiness activity, the MMPA defines “harassment” as (i) Any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) Any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered (Level B harassment). No serious injury or mortality of marine mammals is expected to occur.

Authorized takes would primarily be in the form of Level B harassment, as use of the explosive sources may result, either directly or as result of TTS, in the disruption of natural behavioral patterns to a point where they are abandoned or significantly altered (as defined specifically at the beginning of this section, but referred to generally as behavioral disruption). There is also the potential for Level A harassment, in the form of auditory injury to result from exposure to the sound sources utilized in training and testing activities. As described in this Estimated Take of Marine Mammals section, no non-auditory injury is anticipated or authorized, nor is any serious injury or mortality.

Generally speaking, for acoustic impacts NMFS estimates the amount and type of harassment by considering: (1) acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be taken by Level B harassment or incur some degree of temporary or permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day or event; (3) the density or occurrence of marine mammals within these ensonified areas; and (4) the number of days of activities or events. This analysis of the potential impacts of the planned activities on marine mammals was conducted by using the spatial density models developed by NOAA's Southeast Fisheries Science Center for the species in the Gulf of Mexico (NOAA 2022). The density model integrated visual observations from aerial and shipboard surveys conducted in the Gulf of Mexico from 2003 to 2019.

The munitions planned to be used by each military unit were grouped into mission-day categories so the acoustic impact analysis could be based on the total number of detonations conducted during a given mission to account for the accumulated energy from multiple detonations over a 24-hour period. A total of 19 mission-day categories were developed for the munitions planned to be used. Using the dBSea underwater acoustic model and associated analyses, the threshold distances associated with Level A harassment (PTS) and Level B (TTS and behavioral) harassment zones were estimated for each mission-day category for each marine mammal species. Takes were estimated based on the area of the harassment zones, predicted animal density, and annual number of events for each mission-day category. To assess the potential impacts of inert munitions on marine mammals, the planned inert munitions were categorized into four classes based on their impact energies, and the threshold distances for each class were modeled and calculated as described for the mission-day categories.

Acoustic Thresholds

Using the best available science, NMFS has established acoustic thresholds that identify the most appropriate received level of underwater sound above which marine mammals exposed to these sound sources could be reasonably expected to directly experience a disruption in behavior patterns to a point where they are abandoned or significantly altered, to incur TTS (equated to Level B harassment), or to incur PTS of some degree (equated to Level A harassment). Thresholds have also been developed to identify the pressure levels above which animals may incur non-auditory injury from exposure to pressure waves from explosive detonation. Refer to the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy 2017c) for detailed information on how the criteria and thresholds were derived.

Hearing Impairment (TTS/PTS), Tissues Damage, and Mortality

NMFS' Acoustic Technical Guidance (NMFS 2018) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). The Acoustic Technical Guidance also identifies criteria to predict TTS, which is not considered injury and falls into the Level B harassment category. The USAF's planned activity only includes the use of impulsive (explosives) sources. These thresholds (Table 19) were developed by compiling and synthesizing the best available science and soliciting input multiple times from both the public and peer reviewers. The references, analysis, and methodology used in the development of the thresholds are described in Acoustic Technical Guidance, which may be accessed at:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

Additionally, based on the best available science, NMFS uses the acoustic and pressure thresholds indicated in Table 19 to predict the onset of TTS, PTS, tissue damage, and mortality for explosives (impulsive) and other impulsive sound sources.

Table 19—Onset of TTS, PTS, Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives and Other Impulsive Sources

Functional hearing group

Species

Onset TTS

Onset PTS

Mean onset slight

gastrointestinal (GI)

tract injury

Mean onset slight lung injury

Mean onset mortality

Low-frequency cetaceans

Rice's whale

168 dB SEL (weighted) or 213 dB Peak SPL

183 dB SEL (weighted) or 219 dB Peak SPL

237 dB Peak SPL

Equation 1

Equation 2.

Mid-frequency cetaceans

Dolphins

170 dB SEL (weighted) or 224 dB Peak SPL

185 dB SEL (weighted) or 230 dB Peak SPL

237 dB Peak SPL

Notes:

Equation 1: 47.5M

1/3

(1 + [D

/10.1])

1/6

Pa-sec. Equation 2: 103M

1/3

(1 + [D

/10.1])

1/6

Pa-sec. M = mass of the animals in kg; D

= depth of the receiver (animal) in meters; SPL = sound pressure level.

Refer to the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for detailed information on how the criteria and thresholds were derived. Non-auditory injury (

i.e.,

other than PTS) and mortality are so unlikely as to be discountable under normal conditions and are therefore not considered further in this analysis.

Behavioral Disturbance

Though significantly driven by received level, the onset of Level B harassment by direct behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source (

e.g.,

frequency, predictability, duty cycle, distance), the environment (

e.g.,

bathymetry), and the receiving animals (hearing, motivation, experience, demography, behavioral context) and can be difficult to predict (Ellison

et al.

2011; Southall

et al.

2007). Based on what the available science indicates and the practical need to use thresholds based on a factor or factors that are both predictable and measurable for most activities, NMFS uses generalized acoustic thresholds based primarily on received level (and distance in some cases) to estimate the onset of Level B harassment by behavioral disturbance.

Explosives

—Explosive thresholds for Level B harassment by behavioral disturbance for marine mammals are the hearing groups' TTS thresholds minus 5 dB (see Table 20 below for the TTS thresholds for explosives) for events that contain multiple impulses from explosives underwater. See the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy 2017c) for detailed information on how the criteria and thresholds were derived. NMFS continues to concur that this approach represents the best available science for determining behavioral disturbance of marine mammals from multiple explosives. While marine mammals may also respond to single explosive detonations, these responses are expected to more typically be in the form of startle reaction, rather than a disruption in natural behavioral patterns to the point where they are abandoned or significantly altered. On the rare occasion that a single detonation might result in a more severe behavioral response that qualifies as Level B harassment, it would be expected to be in response to a comparatively higher received level. Accordingly, NMFS considers the potential for these responses to be quantitatively accounted for through the application of the TTS threshold, which, as noted above, is 5 dB higher than the behavioral harassment threshold for multiple explosives. However, the USAF computed behavioral threshold distance and takes for Missions J and K, which are single detonation mission day categories, by using the underwater acoustic model. These model runs were done specifically to estimate behavioral effects (just like other model runs were done to estimate SEL-based TTS and PTS). Behavioral takes were estimated based on the species density within the area exposed to sound levels from 170 dB to 165 dB, where 170 dB SEL is the threshold for TTS. While NMFS considers behavioral harassment at these lower levels unlikely, we have analyzed and authorized these lower-level takes as requested by the USAF to provide coverage in the unlikely event they should occur.

Table 20—Thresholds for Level B Harassment by Behavioral Disturbance for Explosives for Marine Mammals

Medium

Functional

hearing group

SEL

(weighted)

Underwater

163

Underwater

165

Note:

Weighted SEL thresholds in dB re 1 μPa

s underwater. LF = low-frequency, MF = mid-frequency, HF = high-frequency.

USAF's Acoustic Effects Model

The USAF's Acoustic Effects Model calculates sound energy propagation from explosives during USAF activities in the EGTTR. The net explosive weight (NEW) of a munition at impact can be directly correlated with the energy in the impulsive pressure wave generated by the warhead detonation. The NEWs of munitions addressed as part of this final rule range from 0.1 lb (0.04 kg) for small projectiles to 945 lb (428.5kg) for the largest bombs. The explosive materials used in these munitions also vary considerably with different formulations used to produce different intended effects. The primary detonation metrics directly considered and used for modeling analysis are the peak impulse pressure and duration of the impulse. An integration of the pressure of an impulse over the duration (time) of an impulse provides a measure of the energy in an impulse. Some of the NEWs of certain types of munitions, such as missiles, are associated with the propellant used for the flight of the munition. This propellant NEW is unrelated to the NEW of the warhead, which is the primary source of explosive energy in most munitions. The propellant of a missile fuels the flight phase and is mostly consumed prior to impact. Missile propellant typically has a lower flame speed than warhead explosives and is relatively insensitive to detonation from impacts but burns readily. A warhead detonation provides a high-pressure, high-velocity flame front that may cause burning propellant to detonate; therefore, this analysis assumes that the unconsumed residual propellant that remains at impact contributes to the detonation-induced pressure impulse in the water. The impact analysis assumes that 20 percent of the propellant remains unconsumed in missiles at impact; this assumption is based on input from user groups and is considered a reasonable estimate for the purpose of analysis. The NEW associated with this unconsumed propellant is added to the NEW of the warhead to derive the total energy released by the detonation. Absent a warhead detonation, it is assumed that continued burning or deflagration of unconsumed residual propellant does not contribute to the pressure impulse

in the water; this applies to inert missiles that lack a warhead but contain propellant for flight.

In addition to the energy associated with the detonation, energy is also released by the physical impact of the munition with the water. This kinetic energy has been calculated and incorporated into the estimations of munitions energy for both live and inert munitions in this final rule. The kinetic energy of the munition at impact is calculated as one half of the munition mass times the square of the munition velocity. The initial impact event contributing to the pressure impulse in water is assumed to be 1 millisecond in duration. To calculate the velocity (and kinetic energy) immediately after impact, the deceleration contributing to the pressure impulse in the water is assumed for all munitions to be 1,500 g-forces, or 48,300 feet per square second over 1 millisecond. A substantial portion of the change in kinetic energy at impact is dissipated as a pressure impulse in the water, with the remainder being dissipated through structural deformation of the munition, heat, displacement of water, and other smaller energy categories. Even with 1,500 g-forces of deceleration, the change in velocity over this short time period is small and is proportional to the impact velocity and munition mass. The impact energy is the portion of the kinetic energy at impact that is transmitted as an underwater pressure impulse, expressed in units of trinitrotoluene-equivalent (TNTeq). The impact energies of the planned live munitions were calculated and included in their total energy estimations. The impact energies of the inert munitions planned to be used were also calculated. To assess the potential impacts of inert munitions on marine animals, the inert munitions were categorized based on their impact energies into the following four classes of 2 lb (0.9 kg), 1 lb (0.45 kg), 0.5 lb (0.22 kg), and 0.15 lb (0.07 kg) TNTeq; these values correspond closely to the actual or average impact energy values of the munitions and are rounded for the purpose of analysis. The 2 lb class represents the largest inert bomb, whereas the 1 lb class represents the largest inert missile. The inert missile has greater mass but lower impact energy than the bomb; this is because the bomb's lower velocity at impact and associated change in velocity over the deceleration period, which contributes to the pressure impulse. The 0.5 lb and 0.15 lb impact energy classes each represent the approximate average impact energy of multiple munitions, with the 0.5 lb class representing munitions with mid-level energies, and the 0.15 lb class representing munitions with the lowest energies (Table 21).

Table 21—Impact Energy Classes for Inert Munitions

Impact energy class

(lb TNTeq)/(kg)

Approximate weight

(lb)/(kg)

Approximate velocity

(Mach)

2 (0.9)

2,000 (907)

1.1.

1 (0.45)

2,250 (1020.3)

0.9.

0.5 (0.22)

250 to 650 (113.4 to 294.8)

Variable.

0.15 (0.07)

1 to 285 (0.5 to 129.2)

Variable.

The NEW associated with the physical impact of each munition and the unconsumed propellant in certain munitions is added to the NEW of the warhead to derive the NEW at impact (NEWi) for each live munition. The NEWi of each munition was then used to calculate the peak pressure and pressure decay for each munition. This results in a more accurate estimate of the actual energy released by each detonation. Extensive research since the 1940s has shown that each explosive formulation produces unique correlations to explosive performance metrics. The peak pressure and pressure decay constant depend on the NEW, explosive formulation, and distance from the detonation. The peak pressure and duration of the impulse for each munition can be calculated empirically using similitude equations, with constants used in these equations determined from experimental data (Naval Surface Warfare Center (NSWC) 2017). The explosive-specific similitude constants and munition-specific NEWi were used for calculating the peak pressure and pressure decay for each munition analyzed. It should be noted that this analysis assumes that all detonations occur in the water and none of the detonations occur above the water surface when a munition impacts a target. This exceptionally conservative assumption implies that all munition energy is imparted to the water rather than the intended targets. See Appendix A in the LOA application for detailed explanations of similitude equations.

The following standard metrics are used to assess underwater pressure and impulsive noise impacts on marine animals:

• SPL: The SPL for a given munition can be explicitly calculated at a radial distance using the similitude equations.

•

SEL:

A commercially available software package, dBSea (version 2.3), was used to calculate the SEL for each mission day.

•

Positive Impulse:

This is the time integral of the initial positive phase of the pressure impulse. This metric provides a measure of energy in the form of time-integrated pressure. Units are typically pascal-seconds (Pa·s) or pounds per square inch (psi) per millisecond (msec) (psi·msec). The positive impulse for a given munition can be explicitly calculated at a given distance using the similitude equations and integrating the pressure over the initial positive phase of the pressure impulse.

The munition-specific peak pressure and pressure decay at various radii were used to determine the species-specific distance to effect threshold for mortality, non-auditory injury, peak pressure-induced permanent threshold shift (PTS) in hearing and peak pressure-induced temporary threshold shift (TTS) in hearing for each species. The munition-specific peak pressures and decays for all munitions in each mission-day category were used as a time-series input in the dBSea underwater acoustic model to determine the distance to effect for cumulative SEL-based (24-hour) PTS, TTS, and behavioral effects for each species for each mission day.

The dBSea model was conducted using a constant sound speed profile (SSP) of 1500 m/s to be both representative of local conditions and to prevent thermocline induced refractions from distorting the analysis results. Salinity was assumed to be 35 parts per thousand (ppt) and pH was 8. The water surface was treated as smooth (no waves) to conservatively eliminate diffraction induced attenuation of sound. Currents and tidal flow were treated as zero. Energy expended on the target and/or on ejecting water or transfer into air was ignored and all

weapon energy was treated as going into underwater acoustic energy to be conservative. Finally, the bottom was treated as sand with a sound speed of 1650 m/s and an attenuation of 0.8 dB/wavelength.

The harassment zone is the area or volume of ocean in which marine animals could be exposed to various pressure and impulsive noise levels generated by a surface or subsurface detonation that would result in mortality; non-auditory injury and PTS (Level A harassment impacts); and TTS and behavioral impacts (Level B harassment impacts). The harassment zones for the planned detonations were estimated using Version 2.3 of the dBSea model for cumulative SEL and using explicit similitude equations for SPL and positive impulse. The characteristics of the impulse noise at the source were calculated based on munition-specific data including munition mass at impact, munition velocity at impact, NEW of warheads, explosive-specific similitude data, and propellant data for missiles. Table 22 presents the source-level SPLs (at r = 1 meter) calculated for the planned munitions.

Table 22—Calculated Source SPLs for Munitions

Modeled explosive

Model NEWi

(lm)/(kg)

Peak pressure and decay values

Pmax @1 m

(psi)

SPL @1 m dB re 1 mPa

Θ msec

Tritonal

241.36 (109.5)

45961.4858

290.0

0.320

Tritonal

192.3 (87.2)

42101.8577

289.3

0.302

Comp B

98.3 (44.6)

37835.4932

288.3

0.200

PBXN-110

36.18 (13.4)

24704.864

284.6

0.167

PBXN-110

20 (9.1)

19617.2833

282.6

0.143

PBXN-110

13.08 (5.9)

16630.2435

281.2

0.128

PBXN-110

13.08 (5.9)

16630.2435

281.2

0.128

PBXN-9

13.08 (5.9)

17240.2131

281.5

0.124

Comp B

3.8 (1.7)

10187.8419

276.9

0.090

Comp B

4.72 (2.1)

11118.8384

277.7

0.095

Tritonal

36.1 (16.4)

22074.1015

283.7

0.198

Tritonal

36.1 (19.4)

22074.1015

283.7

0.198

PBXN-9

0.49 (0.2)

4757.6146

270.3

0.054

PBXN-9

0.44 (0.2)

4561.06062

270.0

0.053

Tritonal

192.3 (87.2)

42101.8577

289.3

0.302

H-6

100 (45.4)

38017.3815

288.4

0.237

θ = shock wave time constant; dB re 1 μPa = decibel(s) referenced to 1 micropascal; lb = pound(s); lbm = pound-mass; m = meter(s); mm = millimeter(s); msec = millisecond(s); NEWi = net explosive weight at impact; Pmax = shock wave peak pressure; psi = pound(s) per square inch; SPL = sound pressure level;

For SEL analysis, the dBSea model was used with the ray-tracing option for calculating the underwater transmission of impulsive noise sources represented in a time series (1,000,000 samples per second) as calculated using similitude equations (r = 1 meter) for each munition for each mission day. All surface detonations are assumed to occur at a depth of 1 m, and all subsurface detonations, which would include largest bombs and subsurface mines, are assumed to occur at a depth of 3 m. The model used bathymetry for LIA with detonations occurring at the center of the LIA with a water depth of 70 m. The seafloor of the LIA is generally sandy, so sandy bottom characteristics for reflectivity and attenuation were used in the dBSea model, as previously described. The model was used to calculate impulsive acoustic noise transmission on one-third octaves from 31.5 hertz to 32 kilohertz. Maximum SELs from all depths projected to the surface were used for the analyses.

The cumulative SEL is based on multiple parameters including the acoustic characteristics of the detonation and sound propagation loss in the marine environment, which is influenced by a number of environmental factors including water depth and seafloor properties. Based on integration of these parameters, the dBSea model predicts the distances at which each marine animal species is estimated to experience SELs associated with the onset of PTS, TTS, and behavioral disturbance. As noted previously, thresholds for the onset of TTS and PTS used in the model and pressure calculations are based on those presented in Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) (Department of the Navy (DoN) 2017) for cetaceans with mid- to high-frequency hearing (dolphins) and low-frequency hearing (Rice's whale). Behavioral thresholds are set 5 dB below the SEL-based TTS threshold. Table 23 shows calculated SPLs and SELs for the designated mission-day categories.

Table 23—Calculated Source SPLs and SELs for Mission-Day Categories

Mission day

Total warhead NEW, lbm

(kg)

Modeled NEWi,

lbm/(kg)

Source

cumulative

SEL, dB

Source peak

SPL, dB

2402.6 (108.6)

2413.6 (1094.6)

262.1

290

1961 (889.3)

2029.9 (920.6)

261.4

289.3

1145 (519.2)

1376.2 (624.1)

259.8

288.3

562 (254.8)

836.22 (379.2)

257.6

288.3

817.88 (370.9)

997.62 (452.0)

257.1

281.5

584 (264.8)

584.6 (265.1)

256.2

289.3

191(86.6)

191.6 (86.9)

250.4

277.7

60.5 (24.7)

61.1 (27.7)

245.2

268.8

18.4 (8.3)

30.4 (13.8)

242.5

276.9

945 (428.6)

946.8 (429.4)

258.1

294.6

Not available

350 (158.7)

253.4

291.5

624.52 (283.2)

627.12 (284.4)

256.2

290

324 (146.9)

324.9 (147.3)

253.2

283.6

219.92 (99.7)

238.08 (107.9)

252

285.3

72 (36.6)

104.64 (47.5)

248.3

281.2

90 (40.8)

130.8 (59.3)

249.3

281.2

94 (42.6)

94.4 (42.8)

247.5

277.7

35.12 (15.9)

35.82 (16.2)

241.7

270.3

130 (58.9)

249.4

283

lbm = pound-mass.

Mission-Day Categories

The munitions planned to be used by each military unit were grouped into mission-day categories so the acoustic impact analysis could be based on the total number of detonations conducted during a given mission instead of each individual detonation. This analysis was done to account for the accumulated energy from multiple detonations over a 24-hour period.

The estimated number of mission days assigned to each category was based on historical numbers and projections provided by certain user groups. Although the mission-day categories may not represent the exact manner in which munitions would be used, they provide a conservative range of mission scenarios to account for accumulated energy from multiple detonations. It is important to note that only acoustic energy metrics (SEL) are affected by the accumulation of energy over a 24-hour period. Pressure metrics (

e.g.,

peak SPL and positive impulse) do not accumulate and are based on the highest impulse pressure value within the 24-hour period. Based on the categories developed, the total NEWi per mission day would range from 2,413.6 to 30.4 lb (1,094.6 to 13.8 kg). The highest detonation energy of any single munition used under the USAF's planned activities would be 945 lb (428.5 kg) NEW, which was also the highest NEW for a single munition in the previous LOA Request. The munitions having this NEW include the largest bombs.

Note that the types of munitions that would be used for SINKEX testing are controlled information and, therefore, not identified in this LOA Request. For the purpose of analysis, SINKEX exercises are assigned to mission-day category J, which represents a single subsurface detonation of 945 lb NEW. SINKEX exercises would not exceed this NEW. The 2 annual SINKEX exercises are added to the other 8 annual missions involving subsurface detonations of these bombs, resulting in 10 total annual missions under mission-day category J.

As indicated in Table 24, a total of 19 mission-day categories (A through S) were developed as a part of this LOA application. The table also contains information on the number of munitions per day, number of mission days per year, annual quantity of munitions and the NEWi per mission day.

Table 24—Mission-Day Categories for Acoustic Impact Analysis

User group

Mission-day category

Category

NEWi

(lb)/kg

Detonation scenario

Munitions

per day

Mission days per year

Annual

quantity

NEWi per

mission day

(lb)/(kg)

53 WEG

Missile

241.36 (109.4)

Surface

2,413.6 (1,095.9)

Missile

241.36 (109.4)

Surface

Missile

241.36 (109.4)

Surface

Bomb (Mk-82)

192.3 (87.2)

Surface

2,029.9 (920.5)

Bomb (Mk-82)

192.3 (87.2)

Surface

Missile

98.3 (44.6)

Surface

Missile

98.3 (44.6)

Surface

1,376.2 (624.1)

Missile

98.3 (44.6)

Surface

Missile

98.3 (44.6)

Surface

Missile

98.3 (44.6)

Surface

836.22 (379.2)

Missile

36.18 (16.4)

Surface

Missile

20 (9.1)

Surface

Missile

13.08 (5.9)

Surface

997.62 (452.4)

Missile

13.08 (5.9)

Surface

Missile

13.08 (5.9)

Surface

Missile

13.08 (5.9)

Surface

Missile

13.08 (5.9)

Surface

Missile

13.08 (5.9)

Surface

Rocket

3.8 (1.7)

Surface

Missile

13.08 (5.9)

Surface

Gun Ammunition

4.72 (2.1)

Surface

100

Bomb

36.1 (13.3)

Surface

Bomb

36.1 (16.3)

Surface

Missile

Surface

Missile

Surface

Missile

Surface

Missile

Surface

Bomb

0.49 (0.2)

Surface

Bomb

0.44 (0.2)

Surface

AFSOC

Bomb (Mk-82)

192.3 (87.2)

Surface

584.6 (263.1

Bomb

100 (45.3)

Surface

AFSOC

Gun Ammunition

4.72 (2.1)

Surface

25 (daytime)

750

191.6 (86.8)

Gun Ammunition

0.1 (0.01)

Surface

500

12,500

Gun Ammunition

0.37 (0.2)

0.1 (0.01)

Surface

500

45 (nighttime)

1,350

22,500

61.1 (27.7)

Rocket

3.8 (1.7)

Surface

400

30.4 (13.8)

96 OG

Bomb (Mk-84)

946.8 (429.4)

Subsurface

946.8 (429.4)

Hypersonic Weapon

350 (158.7)

Surface

350 (158.7)

Missile

241.36 (109.4)

Surface

627.12 (284.3)

Bomb

72.2 (32.7)

Surface

Bomb

36.1 13.3)

Surface

324.9 (147.3)

Bomb

36.1 (16.3)

Surface

Bomb

36.1 (16.3)

Surface

238.08 (107.9)

Missile

40 (18.1)

Surface

Bomb

22.94 (10.4)

Surface

Missile

13.08 (5.9)

Surface

104.64 (47.5)

Missile

13.08 (5.9)

Surface

130.8 (59.3)

Missile

13.08 (5.9)

Surface

Gun Ammunition

4.72 (2.1)

Surface

94.4 (42.8)

Bomb

0.49 (0.2)

Surface

35.82 (16.2)

Bomb

0.44 (0.2)

Surface

Gun Ammunition

0.37 (0.2)

Surface

Gun Ammunition

0.1 (0.01)

Surface

NAVSCOLEOD

Charge

20 (9.07)

Subsurface

130 (58.9)

Charge

5 (2.3)

Surface

Warhead replaced by FTS/TM. Identified NEW is for the FTS.

Includes 2 SINKEX exercises.

NEW is doubled for simultaneous launch.

Estimated.

Marine Mammal Density

Densities of the common bottlenose dolphin, Atlantic spotted dolphin, and Rice's whale in the study area are based on habitat-based density models and spatial density models developed by the NOAA Southeast Fisheries Science Center for the species in the Gulf of Mexico (NOAA 2022). The density models, herein referred to as the NOAA model, integrated visual observations from aerial and shipboard surveys conducted in the Gulf of Mexico from 2003 to 2019.

The NOAA model was used to predict the average density of the common bottlenose dolphin and Atlantic spotted dolphin in the existing LIA and planned East LIA. The model generates densities for hexagon-shaped raster grids that are 40 square kilometers (km

). The average annual density of each dolphin species in the existing LIA and East LIA was computed in a geographic information system (GIS) based on the densities of the raster grids within the boundaries of each LIA. To account for portions of the grids outside of the LIA, the species density value of each grid was area-weighted based on the respective area of the grid within the LIA. For example, the density of a grid that is 70 percent within the LIA would be weighted to reflect only the 70 percent grid area, which contributes to the average density of the entire LIA. The density of the 30 percent grid area outside the LIA does not contribute to the average LIA density, so it is not included in the estimation. The resulting area-weighted densities of all the grids were summed to determine the average annual density of each dolphin species within each LIA. The densities of dolphins estimated are presented in Table 25.

Table 25—Predicted Dolphin Densities in the Existing LIA and New East LIA

Species

Density estimate

(animals per km

)

Existing LIA

East LIA

Atlantic spotted dolphin

0.032

0.038

Common bottlenose dolphin

0.261

0.317

Estimated average density within LIA based on spatial density model developed by NOAA (2022).

The NOAA model was used to determine Rice's whale density in the exposure analysis conducted for the Rice's whale in this LOA Request. Areas of Rice's whale exposure to pressure and impulsive noise from munitions use, predicted by underwater acoustic modeling and quantified by GIS analysis, were coupled with the associated modeled grid densities from the NOAA model to estimate abundance of affected animals.

Take Estimation

The distances from the live ammunition detonation point that correspond to the various effect thresholds described previously are referred to as threshold distances. The threshold distances were calculated using dBSea for each mission-day category for each marine mammal species. The model was run assuming that the detonation point is at the center

of the existing LIA, the SEL threshold distances are the same for the East LIA, and all missions are conducted in either the existing LIA or East LIA. Model outputs for the two LIAs are statistically the same as a result of similarities in water depths, sea bottom profiles, water temperatures, and other environmental characteristics. Tables 26, 27, and 28 present the threshold distances estimated for the dolphins and Rice's whale, respectively, for live missions in the existing LIA.

The threshold distances were used to calculate the harassment zones for each effect threshold for each species. The thresholds resemble concentric circles, with the most severe (mortality) being closest to the center (detonation point) and the least severe (behavioral disturbance) being farthest from the center. The areas encompassed by the concentric thresholds are the impact areas associated with the applicable criteria. To prevent double counting of animals, areas associated with higher-impact criteria were subtracted from areas associated with lower-impact criteria. To estimate the number of animals potentially exposed to the various thresholds within the harassment zone, the adjusted impact area was multiplied by the predicted animal density and the annual number of events for each mission-day category. The results were rounded at the annual mission-day level and then summed for each criterion to estimate the total annual take numbers for each species. For impulse and SPL metrics, a take is considered to occur if the received level is equal to or above the associated threshold. For SEL metrics, a take is considered to occur if the received level is equal to or above the associated threshold within the appropriate frequency band of the sound received, adjusted for the appropriate weighting function value of that frequency band. For impact categories with multiple criteria (

e.g.,

non-auditory injury and PTS for Level A harassment) and criteria with two thresholds (

e.g.,

SEL and SPL for PTS), the criterion and/or threshold that yielded the higher exposure estimate was used. Threshold distances for dolphins are shown in Table 26 and 27, while Table 28 contains threshold distances for Rice's whale.

Table 26—Bottlenose Dolphin Threshold Distances (in

) for Live Missions in the Existing Live Impact Area

Mission-day category

Mortality

Positive

impulse

B: 248.4 Pa·s

AS: 197.1 Pa·s

Level A harassment

Slight lung

injury

Positive

impulse

B: 114.5 Pa·s

AS: 90.9 Pa·s

tract injury

Peak SPL

237 dB

PTS

Weighted SEL

185 dB

Peak SPL

230 dB

Level B harassment

TTS

Weighted SEL

170 dB

Peak SPL

224 dB

Behavioral

Weighted SEL

165 dB

Bottlenose Dolphin

0.139

0.276

0.194

0.562

0.389

5.59

0.706

9.538

0.128

0.254

0.180

0.581

0.361

5.215

0.655

8.937

0.100

0.199

0.144

0.543

0.289

4.459

0.524

7.568

0.100

0.199

0.144

0.471

0.289

3.251

0.524

5.664

0.068

0.136

0.103

0.479

0.207

3.272

0.377

5.88

0.128

0.254

0.180

0.352

0.362

2.338

0.655

4.596

0.027

0.054

0.048

0.274

0.093

1.095

0.165

2.488

0.010

0.019

0.021

0.225

0.040

0.809

0.071

1.409

0.025

0.049

0.045

0.136

0.087

0.536

0.154

0.918

0.228

0.449

0.306

0.678

0.615

3.458

1.115

6.193

0.158

0.313

0.222

0.258

0.445

1.263

0.808

2.663

0.139

0.276

0.194

0.347

0.389

2.35

0.706

4.656

0.068

0.136

0.103

0.286

0.207

1.446

0.377

3.508

0.073

0.145

0.113

0.25

0.225

1.432

0.404

2.935

0.046

0.092

0.078

0.185

0.155

0.795

0.278

1.878

0.046

0.092

0.078

0.204

0.155

0.907

0.278

2.172

0.027

0.054

0.048

0.247

0.093

0.931

0.165

1.563

0.012

0.024

0.026

0.139

0.052

0.537

0.093

0.91

0.053

0.104

0.084

0.429

0.164

1.699

0.294

2.872

Behavioral threshold for multiple detonations assumes TTS threshold minus 5 dB.

Table 27—Atlantic Spotted Dolphin Threshold Distances (in

) for Live Missions in the Existing Live Impact Area

Mission-day category

Mortality

Positive

impulse

B: 248.4 Pa·s

AS: 197.1 Pa·s

Level A harassment

Slight lung

injury

Positive

impulse

B: 114.5 Pa·s

AS: 90.9 Pa·s

tract injury

Peak SPL

237 dB

PTS

Weighted SEL

185 dB

Peak SPL

230 dB

Level B harassment

TTS

Weighted SEL

170 dB

Peak SPL

224 dB

Behavioral

Weighted SEL

165 dB

Atlantic Spotted Dolphin

0.171

0.338

0.194

0.562

0.389

5.59

0.706

9.538

0.157

0.311

0.180

0.581

0.361

5.215

0.655

8.937

0.123

0.244

0.144

0.543

0.289

4.459

0.524

7.568

0.123

0.244

0.144

0.471

0.289

3.251

0.524

5.664

0.084

0.168

0.103

0.479

0.207

3.272

0.377

5.88

0.157

0.312

0.180

0.352

0.362

2.338

0.655

4.596

0.033

0.066

0.048

0.274

0.093

1.095

0.165

2.488

0.012

0.023

0.021

0.225

0.040

0.809

0.071

1.409

0.030

0.060

0.045

0.136

0.087

0.536

0.154

0.918

0.279

0.550

0.306

0.678

0.615

3.458

1.115

6.193

0.194

0.384

0.222

0.258

0.445

1.263

0.808

2.663

0.171

0.338

0.194

0.347

0.389

2.35

0.706

4.656

0.084

0.168

0.103

0.286

0.207

1.446

0.377

3.508

0.090

0.179

0.113

0.25

0.225

1.432

0.404

2.935

0.057

0.113

0.078

0.185

0.155

0.795

0.278

1.878

0.057

0.113

0.078

0.204

0.155

0.907

0.278

2.172

0.033

0.066

0.048

0.247

0.093

0.931

0.165

1.563

0.015

0.030

0.026

0.139

0.052

0.537

0.093

0.91

0.065

0.128

0.084

0.429

0.164

1.699

0.294

2.872

Behavioral threshold for multiple detonations assumes TTS threshold minus 5 dB.

Table 28—Rice's Whale Threshold Distances (in

) for Live Missions in the Existing Live Impact Area

Mission-day category

Mortality

Positive

impulse

B: 248.4 Pa·s

AS: 197.1 Pa·s

Level A harassment

Slight lung

injury

Positive

impulse

B: 114.5 Pa·s

AS: 90.9 Pa·s

tract injury

Peak SPL

237 dB

PTS

Weighted SEL

185 dB

Peak SPL

230 dB

Level B harassment

TTS

Weighted SEL

170 dB

Peak SPL

224 dB

Behavioral

Weighted SEL

165 dB

0.044

0.088

0.194

5.695

1.170

21.435

2.120

27.923

0.041

0.81

0.180

5.253

1.076

20.641

1.955

26.845

0.031

0.063

0.144

4.332

0.861

18.772

1.562

24.526

0.031

0.063

0.144

2.979

0.861

16.419

1.562

21.579

0.021

0.043

0.103

2.323

0.617

15.814

1.121

21.22

0.041

0.081

0.180

2.208

1.076

14.403

1.955

19.439

0.009

0.017

0.048

0.494

0.266

7.532

0.470

12.92

0.003

0.006

0.021

0.401

0.114

3.624

0.201

7.065

0.008

0.016

0.045

0.305

0.247

2.95

0.437

6.059

0.073

0.145

0.306

4.487

1.830

13.216

3.323

16.88

0.050

0.100

0.222

0.831

1.320

7.723

2.393

11.809

0.044

0.088

0.194

2.325

1.170

15.216

2.120

20.319

0.021

0.043

0.103

1.304

0.617

11.582

1.121

16.688

0.023

0.046

0.113

1.026

0.658

9.904

1.183

14.859

0.015

0.029

0.078

0.611

0.460

6.926

0.832

11.159

0.014

0.029

0.078

0.671

0.460

7.841

0.832

12.307

0.009

0.017

0.048

0.549

0.266

6.299

0.470

10.393

0.004

0.008

0.026

0.283

0.152

2.383

0.273

5.06

0.017

0.034

0.084

0.938

0.473

8.676

0.843

12.874

Behavioral threshold for multiple detonations assumes TTS threshold minus 5 dB.

As discussed previously and shown in Table 21, a portion of the kinetic energy released by an inert munition at impact is transmitted as underwater acoustic energy in a pressure impulse. The planned inert munitions were categorized into four classes based on their impact energies to assess the potential impacts of inert munitions on marine mammals. The threshold distances for each class were modeled and calculated as described for the mission-day categories. Table 29 presents the impact energy classes developed for the inert munitions. The four impact energy classes represent the entire suite of inert munitions planned to be used in the EGTTR during the next mission period. The impact energy is the portion of the kinetic energy at impact that is transmitted as an underwater pressure impulse, expressed in units of TNT-equivalent (TNTeq). Tables 29 and 30 present the threshold distances estimated for the dolphins and Rice's whale, respectively, for inert munitions in the existing LIA.

Table 29—Dolphin Threshold Distances (in

) for Inert Munitions in the Existing Live Impact Area

Inert impact class

(lb TNTeq)

Mortality

Positive

impulse

B: 248.4 Pa·s

AS: 197.1 Pa·s

Level A harassment

Slight lung

injury

Positive

impulse

B: 114.5 Pa·s

AS: 90.9 Pa·s

tract injury

Peak SPL

237 dB

PTS

Weighted SEL

185 dB

Peak SPL

230 dB

Level B harassment

TTS

Weighted SEL

170 dB

Peak SPL

224 dB

Behavioral

Weighted SEL

165 dB

Bottlenose Dolphin

0.020

0.041

0.040

0.030

0.080

0.205

0.145

0.327

0.015

0.031

0.032

0.025

0.063

0.134

0.114

0.250

0.5

0.012

0.023

0.025

0.015

0.050

0.119

0.091

0.198

0.15

0.008

0.015

0.017

0.009

0.034

0.061

0.119

Atlantic Spotted Dolphin

0.025

0.051

0.040

0.030

0.080

0.205

0.145

0.327

0.019

0.038

0.032

0.025

0.063

0.134

0.114

0.250

0.5

0.014

0.029

0.025

0.015

0.050

0.119

0.091

0.198

0.15

0.009

0.018

0.017

0.009

0.034

0.061

0.119

Behavioral threshold for multiple detonations assumes TTS threshold minus 5 dB.

Table 30—Rice's Whale Threshold Distances (in

) for Inert Munitions in the Existing Live Impact Area

Inert impact class

(lb TNTeq)

Mortality

Positive

impulse

906.2 Pa·s

Level A harassment

Slight lung

injury

Positive

impulse

417.9 Pa·s

tract injury

Peak SPL

237 dB

PTS

Weighted SEL

183 dB

Peak SPL

219 dB

Level B harassment

TTS

Weighted SEL

168 dB

Peak SPL

213 dB

Behavioral

Weighted SEL

163 dB

0.006

0.013

0.040

0.151

0.238

0.474

0.430

0.884

0.005

0.010

0.032

0.110

0.188

0.327

0.340

0.542

0.5

0.004

0.007

0.025

0.055

0.149

0.261

0.270

0.521

0.15

0.002

0.005

0.017

0.026

0.100

0.154

0.181

0.284

Behavioral threshold for multiple detonations assumes TTS threshold minus 5 dB.

Dolphin Species

Estimated takes for dolphins are based on the area of the Level A and Level B harassment zones, predicted dolphin density, and annual number of events for each mission-day category. As previously discussed, take estimates for dolphins are based on the average yearly density of each dolphin species in each LIA. To estimate the takes of each dolphin species in both LIAs collectively, the take estimates for each LIA were weighted based on the expected usage of each LIA over the 7-year mission period. This information was provided by the user groups. Ninety percent of the total missions are expected to be conducted in the existing LIA and 10 percent are expected to be conducted in the East LIA. Therefore, total estimated takes are the sum of 90 percent of the takes in the existing LIA and 10 percent of the takes in the East LIA. Should the usage ratio change substantially in the future, USAF would re-evaluate the exposure estimates and reinitiate consultation with NMFS to determine whether the take estimations need to be adjusted.

Table 31—Calculated Annual Exposures of Dolphins Under the USAF's Planned Activities

Mortality

Level A harassment

Injury

PTS

Level B harassment

TTS

Behavioral

Bottlenose Dolphin

Missions at Existing LIA

0.74

2.14

9.25

312.7

799.7

Missions at East LIA

0.89

2.6

11.24

379.79

971.29

90 Percent of Existing LIA Missions

0.66

1.92

8.33

281.4

719.73

10 Percent of East LIA Missions

0.09

0.26

1.12

37.98

97.13

Total

0.75

2.18

9.45

319.14

816.86

Total Takes Requested

319

817

Atlantic Spotted Dolphin

Missions at Existing LIA

0.14

0.39

0.96

38.34

98.05

Missions at East LIA

0.16

0.47

1.14

45.53

116.43

90 Percent of Existing LIA Missions

0.12

0.36

0.86

34.50

88.24

10 Percent of East LIA Missions

0.02

0.05

0.11

4.55

11.64

Total

0.14

0.4

0.98

39.06

99.89

Total Takes

100

Slight lung and/or gastrointestinal tract injury.

The annual exposures of dolphins requested by the USAF and authorized by NMFS are presented in Table 31. As indicated, a total of 9 Level A harassment takes and 1,136 Level B harassment takes of the common bottlenose dolphin, and 1 Level A harassment takes and 139 Level B harassment takes of the Atlantic spotted dolphin are requested annually for EGTTR operations during the next 7-year mission period. The presented takes are overestimates of actual exposure based on the conservative assumption that all planned detonations would occur at or just below the water surface instead of a portion occurring upon impact with targets.

Based on the best available science, the USAF (in coordination with NMFS) used the acoustic and pressure thresholds indicated in Tables 25-29 to predict the onset of tissue damage and mortality for explosives (impulsive) and other impulsive sound sources for inert and live munitions in both the existing LIA and East LIA. The mortality takes calculated for the bottlenose dolphin (0.75) and Atlantic spotted dolphin (0.14) are both less than one animal. Mortality for Rice's whale is zero. Therefore, and in consideration of the required mitigation measures, no mortality takes are requested for either dolphin species or Rice's whale. The non-auditory injury takes are calculated to be 2.18 and 0.40 for the bottlenose dolphin and Atlantic spotted dolphin, respectively. However, these (and the take estimates for the other effect thresholds) are the sum of the respective takes for all 19 mission-day categories. Each individual mission-day category results in a fraction of a non-auditory injury take. Given the required mitigation, adding up all the fractional takes in this manner would likely result in an over-estimate of take. Calculated non-auditory injury for the Rice's whale is zero.

The mitigation measures associated with explosives are expected to be effective in preventing mortality and non-auditory tissue damage to any potentially affected species. All of the calculated distances to mortality or non-auditory injury thresholds are less than 400 m. The USAF would be required to employ trained PSOs to monitor the mitigation zones based on the mission-day activities. The mitigation zone is defined as double the threshold distance at which Level A harassment exposures in the form of PTS could occur (also referred to below as “double the Level A PTS threshold distance”). During pre-monitoring PSOs would be required to postpone or cancel operations if animals are found in these zones. Protected species monitoring would be vessel-based, aerial-based or remote video-based depending on the mission-day activities. The USAF would also be required to conduct testing and training exercises beyond setback distances shown in Table 32. These setback distances would start from the 100-m isobath, which is approximately the shallowest depth where the Rice's whale has been observed. The setback distances are based on the PTS threshold calculated for the Rice's whale depending on the mission-day activity. Also, all gunnery missions must take place 500 m landward of the 100-m isopleth to avoid impacts to the Rice's whale. When these mitigation measures are considered in combination with the modeled exposure results, no species are anticipated to incur mortality or non-auditory tissue damage during the period of this rule.

Based on the conservative assumptions applied to the impact analysis and the pre-mission surveys conducted for dolphins, which extend out to, at a minimum, twice the PTS threshold distance that applies to both dolphin species (185 dB SEL), NMFS has determined that no mortality or non-auditory injury takes are expected and none are authorized for EGTTR operations.

Rice's Whale

Figure 6-2 in the LOA application shows the estimated Rice's whale threshold distances and associated harassment zones for mission-day category A, J, and P and use of a 2 lb class inert munition at the location where the GRATV is typically anchored in the existing LIA. As indicated on Figure 6-2, portions of the behavioral harassment zone of mission-day categories A and J extend into Rice's whale habitat, whereas the monitoring zones for mission-day category P and the largest inert munition are entirely outside Rice's whale habitat. The monitoring zone is defined as the area between double the Level A harassment mitigation zone and the human safety zone perimeter. As previously discussed, the spatial density model developed by NOAA (2022) for the Rice's whale was used to predict Rice's whale density for the purpose of estimating takes. The NOAA model generates densities for hexagon-shaped raster grids that are 40 km

. The specific areas of the raster grids within each of the Level A and Level B harassment zones were computed in GIS and coupled with their respective modeled densities to estimate the number of animals that would be exposed.

Figure 6-3 in the LOA application shows the harassment zones of mission-day category A at the current GRATV anchoring site. As shown, portions of the mitigation zones (TTS and behavioral disturbance) are within grids of modeled density greater than zero individuals per 40 km

. However, the modeled densities in these areas are small and reflect higher occurrence probability for the Rice's whale farther to the southwest, outside the LIA. To estimate annual takes, the number of animals in all model grids within each mitigation, monitoring zone, and Level B harassment (behavioral) zone for all mission-day categories, except gunnery missions (G and H), were computed using the densities from the NOAA model (2022) model and the impact areas calculated in GIS. The modeled densities and the associated areas were multiplied together to estimate abundance within each mitigation, monitoring, and Level B harassment zone. The resulting abundance estimates were summed together and then multiplied by the number of annual missions planned to estimate annual takes. These calculations resulted in a total of 0.04 annual TTS take and 0.10 annual behavioral disturbance take, which indicates that all missions conducted at the current GRATV site

combined would not result in a single Level B harassment take of the Rice's whale. For comparison, Figure 6-4 shows the harassment zones of mission-day category A at the center of the East LIA. As shown, a small portion of the behavioral disturbance zone (27.9 km) encompasses a grid of low modeled density, with grids of higher density being farther to the southwest.

Certain missions could have a PTS impact if they were to be conducted farther to the southwest within the LIAs closer to Rice's whale habitat, as defined by the 100-m isobath. The modeled threshold distances were used to determine the locations in the existing LIA and East LIA where each mission-day category would cause the onset of PTS, measured as a setback from the 100-m isobath. At this setback location, the mission would avoid PTS and result only in non-injury Level B harassment, if one or more Rice's whales were in the affected habitat. The setback distances are based on the longest distance predicted by the dBSea model for a cumulative SEL of 168 dB within the mitigation zone; the predicted average cumulative SEL is used as the basis of effect for estimating takes. The setback distances determined for the mission-day categories are presented in Table 32 and are shown for the existing LIA and East LIA on Figures 6-5 and 6-6, respectively.

Table 32—Setbacks To Prevent Permanent Threshold Shift Impacts to the Rice's Whale

User group

Mission-day