# Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Atlantic Fleet Training and Testing Study Area > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2018-24042 ## Record - **Collection:** Federal Register - **Document type:** Rule - **Published:** November 14, 2018 - **Citation:** 83 FR 57076 ## Text DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 218 [Docket No. 170720687-8965-02] RIN 0648-BH06 Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Atlantic Fleet Training and Testing Study Area AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Final rule. SUMMARY: NMFS, upon request from the U.S. Navy (Navy), issues these regulations pursuant to the Marine Mammal Protection Act (MMPA) to govern the taking of marine mammals incidental to the training and testing activities conducted in the Atlantic Fleet Training and Testing (AFTT) Study Area over the course of five years beginning in November. 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 or stocks and their habitat, and establish requirements pertaining to the monitoring and reporting of such taking. DATES: Effective from November 14, 2018 through November 13, 2023. ADDRESSES: A copy of the Navy's application and supporting documents, as well as a list of the references cited in this document, 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 call the contact listed below (see FOR FURTHER INFORMATION CONTACT ). FOR FURTHER INFORMATION CONTACT: Stephanie Egger, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910, (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. ), establish a framework for authorizing the take of marine mammals incidental to the Navy's training and testing activities (categorized as military readiness activities) from the use of sonar and other transducers, in-water detonations, air guns, impact pile driving/vibratory extraction, and potential vessel strikes based on Navy movement throughout the AFTT Study Area, which includes areas of the western Atlantic Ocean along the East Coast of North America, portions of the Caribbean Sea, and the Gulf of Mexico (GOMEX). We received an application from the Navy requesting five-year regulations and authorizations to incidentally take individuals of multiple species and stocks of marine mammals (“Navy's rulemaking/LOA application” or “Navy's application”). Take is anticipated to occur by Level A and Level B harassment as well as a very small number of serious injuries or mortalities incidental to the Navy's training and testing activities. Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if, after notice and public comment, the agency makes certain findings and issues regulations that set forth permissible methods of taking pursuant to that activity, as well as monitoring and reporting requirements. Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I, provide the legal basis for issuing this final rule and the subsequent LOAs. As directed by this legal authority, this final rule contains mitigation, monitoring, and reporting requirements. Summary of Major Provisions Within the Final Rule Following is a summary of the major provisions of this final rule regarding the Navy's activities. Major provisions include, but are not limited to: The use of defined powerdown and shutdown zones (based on activity); Measures to reduce or eliminate the likelihood of ship strikes, especially for North Atlantic right whales ( Eubalaena glacialis ) (NARW); Operational limitations in certain areas and times that are biologically important ( i.e., for foraging, migration, reproduction) for marine mammals; Implementation of a Notification and Reporting Plan (for dead, live stranded, or marine mammals struck by a vessel); and Implementation of a robust monitoring plan to improve our understanding of the environmental effects resulting from Navy training and testing activities. Additionally, the rule includes an adaptive management component that allows for timely modification of mitigation or monitoring measures based on new information, when appropriate. Background Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq. ) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review and the opportunity to submit comments. An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking, other means of effecting the least practicable adverse impact on the species or stocks, and requirements pertaining to the monitoring and reporting of such takings are set forth. The MMPA states that the term “take” means to harass, hunt, capture, kill or attempt to harass, hunt, capture, or kill any marine mammal. The National Defense Authorization Act of 2004 (2004 NDAA) (Pub. L. 108-136) amended section 101(a)(5) of the MMPA to remove the “small numbers” and “specified geographical region” provisions indicated above and amended the definition of “harassment” as it applies to a “military readiness activity,” along with certain research activities. The definitions of applicable MMPA statutory terms cited above are included in the relevant sections below. More recently, the John S. McCain National Defense Authorization Act for Fiscal Year 2019 (2019 NDAA) (Pub. L. 115-232) amended the MMPA to allow incidental take rules for military readiness activities to be issued for up to seven years. That recent amendment of the MMPA does not affect this final rule. Summary and Background of Request On June 16, 2017, NMFS received an application from the Navy for authorization to take marine mammals incidental to training and testing activities (categorized as military readiness activities) from the use of sonar and other transducers, in-water detonations, air guns, and impact pile driving/vibratory extraction in the AFTT Study Area. In addition, the Navy requested incidental take authorization for up to nine mortalities of four marine mammal species during ship shock trials, and authorization for up to three takes by serious injury or mortality from vessel strikes over the five-year period. On August 4, 2017, the Navy sent an amendment to its application, and the application was found to be adequate and complete. On August 14, 2017 (82 FR 37851), we published a notice of receipt of application (NOR) in the Federal Register , requesting comments and information related to the Navy's request for 30 days. On March 13, 2018, we published a notice of the proposed rulemaking (83 FR 10954) and requested comments and information related to the Navy's request for 45 days. On April 9, 2018, a proposed rule correction (83 FR 15117), which corrected Table 4. Proposed Training was published in the Federal Register . Sections of the table were missing from the preamble, specifically Amphibious Warfare, Anti-Submarine Warfare, Expeditionary Warfare, Mine Warfare, and a portion of Surface Warfare. Comments received during the NOR and the proposed rulemaking comment periods are addressed in this final rule. See further details addressing comments received in the Comments and Responses section. On September 13, 2018, Navy provided NMFS with a memorandum revising the takes by serious injury or mortality included in the Navy's rulemaking/LOA application (Chapter 5, Section 5.2 Incidental Take Request from Vessel Strikes ). Specifically, after further analysis, the Navy withdrew the inclusion of the Western North Atlantic stock of blue whale and the Northern GOMEX stock of sperm whale from its request for authorization for take of three (3) large whales by serious injury or mortality from vessel strike. The information and assessment that supports this change is included in the Estimated Take of Marine Mammals section. The Navy requested two five-year LOAs, one for training and one for testing activities to be conducted within the AFTT Study Area, which includes areas of the western Atlantic Ocean along the East Coast of North America, portions of the Caribbean Sea, and the GOMEX. Please refer to the Navy's rulemaking/LOA application, specifically Figure 1.1-1 for a map of the AFTT Study Area and Figures 2.2-1 through Figure 2.2-3 for additional maps of the range complexes and testing ranges. The following types of training and testing, which are classified as military readiness activities pursuant to the MMPA, as amended by the 2004 NDAA, will be covered under the regulations and associated LOAs: amphibious warfare (in-water detonations), anti-submarine warfare (sonar and other transducers, in-water detonations), expeditionary warfare (in-water detonations), surface warfare (in-water detonations), mine warfare (sonar and other transducers, in-water detonations), and other warfare activities (sonar and other transducers, impact pile driving/vibratory extraction, air guns). In addition, ship shock trials, a specific testing activity related to vessel evaluation, will be conducted. Also, ship strike by Navy vessels is addressed and covered, as appropriate. This will be NMFS' third series of rulemaking under the MMPA for activities in the AFTT Study Area. NMFS published the first rule effective from January 22, 2009 through January 22, 2014 on January 27, 2009 (74 FR 4844) and the second rule effective from November 14, 2013 through November 13, 2018 on December 4, 2013 (78 FR 73009). These regulations are also valid for five years, from November 14, 2018, through November 13, 2023. The Navy's mission is to organize, train, equip, and maintain combat-ready naval forces capable of winning wars, deterring aggression, and maintaining freedom of the seas. This mission is mandated by federal law (10 U.S.C. 5062), which ensures the readiness of the naval forces of the United States. The Navy executes this responsibility by establishing and executing training and testing programs, including at-sea training and testing exercises, and ensuring naval forces have access to the ranges, operating areas (OPAREAs), and airspace needed to develop and maintain skills for conducting naval activities. The Navy plans to conduct training and testing activities within the AFTT Study Area. The Navy has been conducting military readiness activities in the AFTT Study Area for well over a century and with active sonar for over 70 years. The tempo and types of training and testing activities have fluctuated because of the introduction of new technologies, the evolving nature of international events, advances in warfighting doctrine and procedures, and changes in force structure (organization of ships, weapons, and personnel). Such developments influenced the frequency, duration, intensity, and location of required training and testing activities. This rulemaking reflects the most up to date compilation of training and testing activities deemed necessary to accomplish military readiness requirements. The types and numbers of activities included in the rule accounts for fluctuations in training and testing in order to meet evolving or emergent military readiness requirements. These regulations cover training and testing activities that would occur for a five-year period following the expiration of the current MMPA authorization for the AFTT Study Area, which expires on November 13, 2018. Description of the Specified Activity Additional detail regarding the specified activity was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Since the proposed rule, the Navy has removed one of its testing activities in the Northeast Range Complex (four events for Undersea Warfare Testing (USWT), which decreased the number of takes by Level B harassment for the NARW by 115 takes annually. This change also decreased take by Level B harassment by approximately 200 takes annually for Endangered Species Act (ESA)-listed fin whale and 20 takes annually for sei whales as well as approximately 10,000 takes annually for harbor porpoise. NMFS and the Navy have also reached agreement on additional mitigation measures since the proposed rule, which are summarized below and discussed in greater detail in the Mitigation Measures section of this rule. The Navy agrees to implement pre- and post-event observations as part of all in-water explosive event mitigations in the AFTT Study Area. The Navy has expanded the Northeast (NE) NARW Mitigation Area to match the updated NE NARW ESA-designated critical habitat. The Navy has agreed to broadcast awareness notification messages with NARW Dynamic Management Area information ( e.g., location and dates) to alert vessels to the possible presence of a NARW to further reduce the potential for a vessel strike. The Navy has agreed to additional coordination to aid in the implementation of procedural mitigation to minimize potential interactions with NARW in the Jacksonville Operating Area. The Navy will also report the total hours and counts of active sonar and in-water explosives used in a Southeast (SE) NARW Critical Habitat Special Reporting Area in its annual training and testing activity reports submitted to NMFS. The Navy will minimize use of explosives (March to September) in the Navy Cherry Point Range Complex Nearshore Mitigation Area to the extent practicable. In addition, the Navy will not conduct major training exercises (MTE) in the Gulf of Maine Planning Awareness Mitigation Area and the GOMEX Planning Awareness Mitigation Area. The Navy will also implement a 200 hour (hr)/year hull-mounted mid-frequency active sonar (MFAS) cap in the Gulf of Maine Planning Awareness Mitigation Area. The Navy has added a year-round, Bryde's Whale Mitigation Area, which will cover the biologically important area (BIA) as described in NMFS' 2016 Status Review (NMFS 2016) and implement a 200 hr/year hull-mounted MFAS cap and restrict all explosives except for mine warfare activities events in this mitigation area. The Navy has assessed and agreed to move the ship shock trial box east of the Mid-Atlantic Planning Awareness Mitigation Areas and move the northern GOMEX ship shock trial west of the Bryde's Whale Mitigation Area, including five nmi buffers from the mitigation areas. The Navy has also revised its estimated serious injury or mortality takes of large whales and, as a result, withdrawn its request for serious injury or mortality incidental take for the Western North Atlantic stock of blue whale and Northern GOMEX stock of sperm whale due to the extremely low probability that vessel strike incidental to the training and testing activities in the AFTT Study Area would occur. Overview of Training and Testing Activities The Navy routinely trains and tests in the AFTT Study Area in preparation for national defense missions. Training and testing activities and exercises covered in these regulations are summarized below. Primary Mission Areas The Navy categorizes its activities into functional warfare areas called primary mission areas. These activities generally fall into the following seven primary mission areas: Air warfare; amphibious warfare; anti-submarine warfare (ASW); electronic warfare; expeditionary warfare; mine warfare (MIW); and surface warfare (SUW). Most activities addressed in the AFTT Final Environmental Impact Statement/Overseas Environmental Impact Statement (FEIS/OEIS) are categorized under one of the primary mission areas; the testing community has three additional categories of activities for vessel evaluation (including ship shock trials), unmanned systems, and acoustic and oceanographic science and technology. Activities that do not fall within one of these areas are listed as “other warfare activities.” Each warfare community (surface, subsurface, aviation, and expeditionary warfare) may train in some or all of these primary mission areas. The testing community also categorizes most, but not all, of its testing activities under these primary mission areas. The Navy describes and analyzes the impacts of its training and testing activities within the AFTT FEIS/OEIS and the Navy's rulemaking/LOA application (documents available at www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities ). In its assessment, the Navy concluded that sonar and other transducers, in-water detonations, air guns, and pile driving/extraction were the stressors that would result in impacts on marine mammals that could rise to the level of harassment (also serious injury or mortality in ship shock trials or by vessel strike) as defined under the MMPA. Therefore, the rulemaking/LOA application provides the Navy's assessment of potential effects from these stressors in terms of the various warfare mission areas in which they would be conducted. In terms of Navy's primary warfare areas, this includes: • Amphibious warfare (in-water detonations); • anti-submarine warfare (sonar and other transducers, in-water detonations); • expeditionary warfare (in-water detonations); • surface warfare (in-water detonations); • mine warfare (sonar and other transducers, in-water detonations); and • other warfare activities (sonar and other transducers, impact pile driving/vibratory extraction, air guns). Overview of Training Activities and Exercises Within the AFTT Study Area An MTE is comprised of several “unit level” range exercises conducted by several units operating together while commanded and controlled by a single commander. These exercises typically employ an exercise scenario developed to train and evaluate the strike group in naval tactical tasks. In a MTE, most of the activities being directed and coordinated by the strike group commander are identical in nature to the activities conducted during individual, crew, and smaller unit level training events. In a MTE, however, these disparate training tasks are conducted in concert, rather than in isolation. Some integrated or coordinated ASW exercises are similar in that they are comprised of several unit level exercises but are generally on a smaller scale than a MTE, are shorter in duration, use fewer assets, and use fewer hours of hull-mounted sonar per exercise. These coordinated exercises are conducted under anti-submarine warfare. For the purpose of analysis, three key factors used to identify and group the exercises are the scale of the exercise, duration of the exercise, and amount of hull-mounted sonar hours modeled/used for the exercise. NMFS considered the effects of all training exercises, not just the major training exercises in these regulations. Additional detail regarding the training activities was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018) and a proposed rule correction (83 FR 15117; April 9, 2018); please see those documents or the Navy's application for more information. Overview of Testing Activities Within the AFTT Study Area The Navy's research and acquisition community engages in a broad spectrum of testing activities in support of the fleet. These activities include, but are not limited to, basic and applied scientific research and technology development; testing, evaluation, and maintenance of systems ( e.g., missiles, radar, and sonar) and platforms ( e.g., surface ships, submarines, and aircraft); and acquisition of systems and platforms to support Navy missions and give a technological edge over adversaries. The individual commands within the research and acquisition community included in the Navy's rulemaking/LOA application are the Naval Air Systems Command, Naval Sea Systems Command, and the Office of Naval Research. Additional detail regarding the testing activities was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Dates and Duration The specified activities may occur at any time during the five-year period of validity of the regulations. Planned number and duration of training and testing activities are shown in the Planned Activities section (Tables 4 through 7). Specific Geographic Area The Navy's training and testing activities conducted within the AFTT Study Area (which includes areas of the western Atlantic Ocean along the East Coast of North America, portions of the Caribbean Sea, and the GOMEX), covers approximately 2.6 million square nautical miles (nmi 2 ) of ocean area, oriented from the mean high tide line along the U.S. coast and extends east to the 45-degree west longitude line, north to the 65-degree north latitude line, and south to approximately the 20-degree north latitude line. Please refer to the Navy's rulemaking/LOA application, specifically Figure 1.1-1 for a map of the AFTT Study Area and Figures 2.2-1 through Figure 2.2-3 for additional maps of the range complexes and testing ranges. Description of Acoustic and Explosive Stressors The planned training and testing activities were evaluated to identify specific components that could act as stressors (acoustic and explosive) by having direct or indirect impacts on the environment. This analysis included identification of the spatial variation of the identified stressors. The Navy uses a variety of sensors, platforms, weapons, and other devices, including ones used to ensure the safety of Sailors and Marines, to meet its mission. Training and testing with these systems may introduce acoustic (sound) energy into the environment. The Navy's rulemaking/LOA application describes specific components that could act as stressors by having direct or indirect impacts on the environment. This analysis included identification of the spatial variation of the identified stressors. The following subsections describe the acoustic and explosive stressors for biological resources within the AFTT Study Area. Because of the complexity of analyzing sound propagation in the ocean environment, the Navy relies on acoustic models in its environmental analyses that consider sound source characteristics and varying ocean conditions across the AFTT Study Area. Stressor/resource interactions that were determined to have de minimus or no impacts ( i.e., vessel, aircraft, or weapons noise) were not carried forward for analysis in the Navy's rulemaking/LOA application. NMFS reviewed the Navy's analysis and conclusions and finds them complete and supportable. Acoustic Stressors Acoustic stressors include acoustic signals emitted into the water for a specific purpose, such as sonar, other transducers (devices that convert energy from one form to another—in this case, to sound waves), and air guns, as well as incidental sources of broadband sound produced as a byproduct of impact pile driving and vibratory extraction. Explosives also produce broadband sound but are characterized separately from other acoustic sources due to their unique characteristics. In order to better organize and facilitate the analysis of approximately 300 sources of underwater sound used for training and testing by the Navy including sonars, other transducers, air guns, and explosives, a series of source classifications, or source bins, were developed. The source classification bins do not include the broadband sounds produced incidental to pile driving, vessel or aircraft transits, weapons firing, and bow shocks. The use of source classification bins provides the following benefits: Provides the ability for new sensors or munitions to be covered under existing authorizations, as long as those sources fall within the parameters of a “bin;” improves efficiency of source utilization data collection and reporting requirements anticipated under the MMPA authorizations; ensures a conservative approach to all impact estimates, as all sources within a given class are modeled as the most impactful source (highest source level, longest duty cycle, or largest net explosive weight) within that bin; allows analyses to be conducted in a more efficient manner, without any compromise of analytical results; and provides a framework to support the reallocation of source usage (hours/explosives) between different source bins, as long as the total numbers of takes remain within the overall analyzed and authorized limits. This flexibility is required to support evolving Navy training and testing requirements, which are linked to real world events. Sonar and Other Transducers Active sonar and other transducers emit non-impulsive sound waves into the water to detect objects, safely navigate, and communicate. Passive sonars differ from active sound sources in that they do not emit acoustic signals; rather, they only receive acoustic information about the environment, or listen. The Navy employs a variety of sonars and other transducers to obtain and transmit information about the undersea environment. Some examples are mid-frequency hull-mounted sonars used to find and track enemy submarines; high-frequency small object detection sonars used to detect mines; high frequency underwater modems used to transfer data over short ranges; and extremely high-frequency (>200 kilohertz [kHz]) Doppler sonars used for navigation, like those used on commercial and private vessels. Additional detail regarding sound sources and platforms and categories of acoustic stressors was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Sonars and other transducers are grouped into classes that share an attribute, such as frequency range or purpose of use. Classes are further sorted by bins based on the frequency or bandwidth; source level; and, when warranted, the application in which the source would be used, as follows: Frequency of the non-impulsive acoustic source; ○ Low-frequency sources operate below 1 kHz; ○ Mid-frequency sources operate at and above 1 kHz, up to and including 10 kHz; ○ High-frequency sources operate above 10 kHz, up to and including 100 kHz; ○ Very high-frequency sources operate above 100 kHz but below 200 kHz; Sound pressure level of the non-impulsive source; ○ Greater than 160 decibels (dB) re 1 micro Pascal (μPa), but less than 180 dB re 1 μPa; ○ Equal to 180 dB re 1 μPa and up to 200 dB re 1 μPa; ○ Greater than 200 dB re 1 μPa; Application in which the source would be used; ○ Sources with similar functions that have similar characteristics, such as pulse length (duration of each pulse), beam pattern, and duty cycle. The bins used for classifying active sonars and transducers that are quantitatively analyzed in the AFTT Study Area are shown in Table 1 below. While general parameters or source characteristics are shown in the table, actual source parameters are classified. Table 1—Sonar and Transducers Quantitatively Analyzed in the AFTT Study Area Source class category Bin Description Low-Frequency (LF): Sources that produce signals less than 1 kHz LF3 LF4 LF sources greater than 200 dB. LF sources equal to 180 dB and up to 200 dB. LF5 LF sources less than 180 dB. LF6 LF sources greater than 200 dB with long pulse lengths. Mid-Frequency (MF): Tactical and non-tactical sources that produce signals between 1-10 kHz MF1 Hull-mounted surface ship sonars ( e.g., AN/SQS-53C and AN/SQS-61). MF1K Kingfisher mode associated with MF1 sonars. MF3 Hull-mounted submarine sonars ( e.g., AN/BQQ-10). MF4 Helicopter-deployed dipping sonars ( e.g., AN/AQS-22 and AN/AQS-13). MF5 Active acoustic sonobuoys ( e.g., DICASS). MF6 Active underwater sound signal devices ( e.g., MK84). MF8 Active sources (greater than 200 dB) not otherwise binned. MF9 Active sources (equal to 180 dB and up to 200 dB) not otherwise binned. MF10 Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned. MF11 Hull-mounted surface ship sonars with an active duty cycle greater than 80%. MF12 Towed array surface ship sonars with an active duty cycle greater than 80%. MF14 Oceanographic MF sonar. High-Frequency (HF): Tactical and non-tactical sources that produce signals between 10-100 kHz HF1 Hull-mounted submarine sonars ( e.g., AN/BQQ-10). HF3 Other hull-mounted submarine sonars (classified). HF4 Mine detection, classification, and neutralization sonar ( e.g., AN/SQS-20). HF5 Active sources (greater than 200 dB) not otherwise binned. HF6 Active sources (equal to 180 dB and up to 200 dB) not otherwise binned. HF7 Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned. HF8 Hull-mounted surface ship sonars ( e.g., AN/SQS-61). Very High-Frequency Sonars (VHF): Non-tactical sources that produce signals between 100-200 kHz VHF1 VHF sources greater than 200 dB. Anti-Submarine Warfare (ASW): Tactical sources (e.g., active sonobuoys and acoustic counter-measures systems) used during ASW training and testing activities ASW1 MF systems operating above 200 dB. ASW2 MF Multistatic Active Coherent sonobuoy ( e.g., AN/SSQ-125). ASW3 MF towed active acoustic countermeasure systems ( e.g., AN/SLQ-25). ASW4 MF expendable active acoustic device countermeasures ( e.g., MK 3). ASW5 MF sonobuoys with high duty cycles. Torpedoes (TORP): Source classes associated with the active acoustic signals produced by torpedoes TORP1 Lightweight torpedo ( e.g., MK 46, MK 54, or Anti-Torpedo Torpedo). TORP2 Heavyweight torpedo ( e.g., MK 48). TORP3 Heavyweight torpedo ( e.g., MK 48). Forward Looking Sonar (FLS): Forward or upward looking object avoidance sonars used for ship navigation and safety FLS2 HF sources with short pulse lengths, narrow beam widths, and focused beam patterns. Acoustic Modems (M): Systems used to transmit data through the water M3 MF acoustic modems (greater than 190 dB). Swimmer Detection Sonars (SD): Systems used to detect divers and sub- merged swimmers SD1-SD2 HF and VHF sources with short pulse lengths, used for the detection of swimmers and other objects for the purpose of port security. Synthetic Aperture Sonars (SAS): Sonars in which active acoustic signals are post-processed to form high-resolution images of the seafloor SAS1 MF SAS systems. SAS2 HF SAS systems. SAS3 VHF SAS systems. SAS4 MF to HF broadband mine countermeasure sonar. Broadband Sound Sources (BB): Sonar systems with large frequency spectra, used for various purposes BB1 MF to HF mine countermeasure sonar. BB2 HF to VHF mine countermeasure sonar. BB4 LF to MF oceanographic source. BB5 LF to MF oceanographic source. BB6 HF oceanographic source. BB7 LF oceanographic source. Notes: ASW: Anti-submarine Warfare; BB: Broadband Sound Sources; FLS: Forward Looking Sonar; HF: High-Frequency; LF: Low-Frequency; M: Acoustic Modems; MF: Mid-Frequency; SAS: Synthetic Aperture Sonars; SD: Swimmer Detection Sonars; TORP: Torpedoes; VHF: Very High-Frequency; dB: decibels. Air guns Small air guns with capacities up to 60 cubic inches (in 3 ) would be used during testing activities in various offshore areas in the AFTT Study Area, as well as near shore at Newport, RI. Generated impulses would have short durations, typically a few hundred milliseconds, with dominant frequencies below 1 kHz. The root-mean-square sound pressure level (SPL) and peak pressure (SPL peak) at a distance 1 meter (m) from the airgun would be approximately 215 dB re 1 μPa and 227 dB re 1 μPa, respectively, if operated at the full capacity of 60 in 3 cubic inches. Pile Driving/Extraction Impact pile driving and vibratory pile removal would occur during construction of an Elevated Causeway System (ELCAS), a temporary pier that allows the offloading of ships in areas without a permanent port. The source levels of the noise produced by impact pile driving and vibratory pile removal from an actual elevated causeway pile driving and removal are shown in Table 2. Table 2—Elevated Causeway System Pile Driving and Removal Underwater Sound Levels in the AFTT Study Area Pile size and type Method Average sound levels at 10 m 24-in. Steel Pipe Pile Impact 1 192 dB re 1 µPa SPL rms; 182 dB re 1 µPa 2 s SEL (single strike). 24-in. Steel Pipe Pile Vibratory 2 146 dB re 1 µPa SPL rms; 145 dB re 1 µPa 2 s SEL (per second of duration). 1 Illingworth and Rodkin (2016). 2 Illingworth and Rodkin (2015). Notes: dB re 1 µPa: decibels referenced to 1 micropascal; in.: inch; rms: root mean squared; SEL: Sound Exposure Level; SPL: Sound Pressure Level. The size of the pier in an ELCAS event is approximately 1,520 ft long, requiring 119 supporting piles. Construction of the ELCAS would involve intermittent impact pile driving over approximately 20 days. Crews work 24 hours (hrs) a day and would drive approximately 6 piles in that period. Each pile takes about 15 minutes to drive with time taken between piles to reposition the driver. When training events that use the ELCAS are complete, the structure would be removed using vibratory methods over approximately 10 days. Crews would remove about 12 piles per 24-hour period, each taking about 6 minutes to remove. Explosive Stressors This section describes the characteristics of explosions during naval training and testing. The activities analyzed in the Navy's rulemaking/LOA application that use explosives are described in Appendix A (Navy Activity Descriptions) of the AFTT FEIS/OEIS. Additional detail regarding explosive stressors was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Explosive detonations during training and testing activities are associated with high-explosive munitions, including, but not limited to, bombs, missiles, rockets, naval gun shells, torpedoes, mines, demolition charges, and explosive sonobuoys. Explosive detonations during training and testing involving the use of high-explosive munitions (including bombs, missiles, and naval gun shells) could occur near the water's surface. Explosive detonations associated with torpedoes and explosive sonobuoys would occur in the water column; mines and demolition charges could be detonated in the water column or on the ocean bottom. Most detonations would occur in waters greater than 200 ft in depth, and greater than 3 nmi from shore, although mine warfare, demolition, and some testing detonations would occur in shallow water close to shore. In order to better organize and facilitate the analysis of explosives used by the Navy during training and testing that could detonate in water or at the water surface, explosive classification bins were developed. Explosives detonated in water are binned by net explosive weight. The bins of explosives that are planned for use in the AFTT Study Area are shown in Table 3 below. Table 3—Explosives Analyzed in the AFTT Study Area Bin Net explosive weight 1 (lb) Example explosive source E1 0.1-0.25 Medium-caliber projectile. E2 >0.25-0.5 Medium-caliber projectile. E3 >0.5-2.5 Large-caliber projectile. E4 >2.5-5 Mine neutralization charge. E5 >5-10 5-inch projectile. E6 >10-20 Hellfire missile. E7 >20-60 Demo block/shaped charge. E8 >60-100 Light-weight torpedo. E9 >100-250 500 lb. bomb. E10 >250-500 Harpoon missile. E11 >500-650 650 lb mine. E12 >650-1,000 2,000 lb bomb. E14 2 >1,741-3,625 Line charge. E16 >7,250-14,500 Littoral Combat Ship full ship shock trial. E17 >14,500-58,000 Aircraft carrier full ship shock trial. 1 Net Explosive Weight refers to the equivalent amount of TNT the actual weight of a munition may be larger due to other components. 2 E14 is not modeled for protected species impacts in water because most energy is lost into the air or to the bottom substrate due to detonation in very shallow water. Explosive Fragments Marine mammals could be exposed to fragments from underwater explosions associated with the specified activities. When explosive ordnance ( e.g., bombs or missiles) detonates, fragments of the weapons are thrown at high-velocity from the detonation point, which can injure or kill marine mammals if they are struck. These fragments may be of variable size and are ejected at supersonic speed from the detonation. The casing fragments will be ejected at velocities much greater than debris from any target due to the proximity of the casing to the explosive material. Risk of fragment injury reduces exponentially with distance as the fragment density is reduced. Fragments underwater tend to be larger than fragments produced by in-air explosions (Swisdak and Montaro, 1992). Underwater, the friction of the water would quickly slow these fragments to a point where they no longer pose a threat. In contrast, the blast wave from an explosive detonation moves efficiently through seawater. Because the ranges to mortality and injury due to exposure to the blast wave are likely to far exceed the zone where fragments could injure or kill an animal, the threshold are assumed to encompass risk due to fragmentation. Other Stressor—Vessel Strike Vessel strikes are not specific to any particular training or testing activity, but rather a potential, limited, sporadic, and incidental result of Navy vessel movement within the AFTT Study Area. The average speed of large Navy ships ranges between 10 and 15 knots and submarines generally operate at speeds in the range of 8-13 knots, while a few specialized vessels can travel at faster speeds. Vessel strikes are likely to result in incidental take from serious injury and/or mortality and, accordingly, for the purposes of the analysis we assume that any authorized ship strike would result in serious injury or mortality. Information on Navy vessel movements is provided in the Planned Activities section. Additional detail on vessel strike was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Additionally, as referenced above and described in more detail in the Estimated Take of Marine Mammals section, on September 13, 2018 the Navy provided additional information explaining why and withdrew certain species from their request for serious injury or mortality takes from vessel strike. Planned Activities Planned Training Activities The training activities that the Navy plans to conduct in the AFTT Study Area are summarized in Table 4. The table is organized according to primary mission areas and includes the activity name, associated stressors applicable to these regulations, number of planned activities, and locations of those activities in the AFTT Study Area. For further information regarding the primary platform used ( e.g., ship or aircraft type) see Appendix A (Navy Activity Descriptions) of the AFTT FEIS/OEIS. ER14NO18.016 ER14NO18.017 ER14NO18.018 ER14NO18.019 ER14NO18.020 ER14NO18.021 ER14NO18.022 ER14NO18.023 Planned Testing Activities Testing activities covered in these regulations are described in Table 5 through Table 7. Naval Air Systems Command Table 5 summarizes the planned testing activities for the Naval Air Systems Command analyzed within the AFTT Study Area. ER14NO18.024 ER14NO18.025 ER14NO18.026 ER14NO18.027 Naval Sea Systems Command Table 6 summarizes the planned testing activities for the Naval Sea Systems Command analyzed within the AFTT Study Area. ER14NO18.028 ER14NO18.029 ER14NO18.030 ER14NO18.031 ER14NO18.032 ER14NO18.033 ER14NO18.034 ER14NO18.035 Office of Naval Research Table 7 summarizes the planned testing activities for the Office of Naval Research analyzed within the AFTT Study Area. ER14NO18.036 Summary of Acoustic and Explosive Sources Analyzed for Training and Testing Table 8 through Table 11 show the acoustic source classes and numbers, explosive source bins and numbers, air gun sources, and pile driving and removal activities associated with Navy training and testing activities in the AFTT Study Area that were analyzed in this rule. Table 8 shows the acoustic source classes ( i.e., LF, MF, and HF) that could occur in any year under the Planned Activity for training and testing activities. Under the Planned Activities, acoustic source class use would vary annually, consistent with the number of annual activities summarized above. The five-year total for the Planned Activities takes into account that annual variability. ER14NO18.037 ER14NO18.038 ER14NO18.039 ER14NO18.040 Table 9 shows the number of air gun shots planned in AFTT Study Area for training and testing activities. Table 9—Training and Testing Airgun Sources Quantitatively Analyzed in the AFTT Study Area Source class category Bin Unit 1 Training Annual 5-year total Testing Annual 5-year total Air guns (AG): Small underwater air guns AG C 0 0 604 3,020 1 C = count. One count (C) of AG is equivalent to 100 air gun firings. Table 10 summarizes the impact pile driving and vibratory pile removal activities that would occur during a 24-hour period. Annually, for impact pile driving, the Navy will drive 119 piles, two times a year for a total of 238 piles. Over the 5-year period of the rule, the Navy will drive a total of 1190 piles by impact pile driving. Annually, for vibratory pile removal, the Navy will remove 119 piles, two times a year for a total of 238 piles. Over the 5-year period of the rule, the Navy will remove a total of 1190 piles by vibratory pile removal. Table 10—Summary of Pile Driving and Removal Activities per 24-Hour Period in the AFTT Study Area Method Piles per 24-hour period Time per pile (minutes) Total estimated time of noise per 24-hour period (minutes) Pile Driving (Impact) 6 15 90 Pile Removal (Vibratory) 12 6 72 Table 11 shows the number of in-water explosives that could be used in any year under the Planned Activity for training and testing activities. Under the Planned Activities, bin use would vary annually, consistent with the number of annual activities summarized above. The five-year total for the Specified Activities takes into account that annual variability. Table 11-Explosive Source Bins Analyzed and Numbers Used During Training and Testing Activities in the AFTT Study Area Bin Net explosive weight 1 (lb) Example explosive source Training Annual 2 5-year total Testing Annual 2 5-year total E1 0.1-0.25 Medium-caliber projectile 7,700 38,500 17,840-26,840 116,200 E2 >0.25-0.5 Medium-caliber projectile 210-214 1,062 0 0 E3 >0.5-2.5 Large-caliber projectile 4,592 22,960 3,054-3,422 16,206 E4 >2.5-5 Mine neutralization charge 127-133 653 746-800 3,784 E5 >5-10 5-inch projectile 1,436 7,180 1,325 6,625 E6 >10-20 Hellfire missile 602 3,010 28-48 200 E7 >20-60 Demo block/shaped charge 4 20 0 0 E8 >60-100 Light-weight torpedo 22 110 33 165 E9 >100-250 500 lb bomb 66 330 4 20 E10 >250-500 Harpoon missile 90 450 68-98 400 E11 >500-650 650 lb mine 1 5 10 50 E12 >650-1,000 2,000 lb bomb 18 90 0 0 E16 3 >7,250-14,500 Littoral Combat Ship full ship shock trial 0 0 0-12 12 E17 3 >14,500-58,000 Aircraft carrier full ship shock trial 0 0 0-4 4 1 Net Explosive Weight refers to the equivalent amount of TNT the actual weight of a munition may be larger due to other components. 2 Expected annual use may vary per bin because the number of events may vary from year to year, as described in Section 1.5 (Planned Activity). 3 Shock trials consist of four explosions each. In any given year there could be 0-3 small ship shock trials (E16) and 0-1 large ship shock trials (E17). Over a 5-year period, there could be three small ship shock trials (E16) and one large ship shock trial (E17). Vessel Movement Vessels used as part of the Planned Activity include ships, submarines and boats ranging in size from small, 22 ft (7 m) rigid hull inflatable boats to aircraft carriers with lengths up to 1,092 ft (333 m). Large Navy ships greater than 60 ft (18 m) generally operate at speeds in the range of 10 to 15 kn for fuel conservation. Submarines generally operate at speeds in the range of 8 to 13 kn in transits and less than those speeds for certain tactical maneuvers. Small craft, less than 60 ft (18 m) in length, have much more variable speeds (dependent on the mission). For small craft types, sizes and speeds vary during training and testing. Speeds generally range from 10 to 14 kn. While these speeds for large and small crafts are representative of most events, some vessels need to temporarily operate outside of these parameters. The number of Navy vessels used in the AFTT Study Area varies based on military training and testing requirements, deployment schedules, annual budgets, and other unpredictable factors. Most training and testing activities involve the use of vessels. These activities could be widely dispersed throughout the AFTT Study Area, but would be typically conducted near naval ports, piers, and range areas. Standard Operating Procedures For training and testing to be effective, personnel must be able to safely use their sensors and weapon systems as they are intended to be used in a real-world situation and to their optimum capabilities. While standard operating procedures are designed for the safety of personnel and equipment and to ensure the success of training and testing activities, their implementation often yields additional benefits on environmental, socioeconomic, public health and safety, and cultural resources. Because standard operating procedures are essential to safety and mission success, the Navy considers them to be part of the planned activities and has included them in the environmental analysis. Additional details on standard operating procedures were provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Duration and Location Training and testing activities would be conducted in the AFTT Study Area throughout the year from 2018 through 2023 for the five-year period covered by the regulations. The AFTT Study Area (see Figure 1.1-1 of the Navy's rulemaking/LOA application) includes areas of the western Atlantic Ocean along the East Coast of North America, portions of the Caribbean Sea, and the GOMEX. The AFTT Study Area begins at the mean high tide line along the U.S. coast and extends east to the 45-degree west longitude line, north to the 65-degree north latitude line, and south to approximately the 20-degree north latitude line. The AFTT Study Area also includes Navy pierside locations, bays, harbors, and inland waterways, and civilian ports where training and testing occurs. The AFTT Study Area generally follows the Commander Task Force 80 area of operations, covering approximately 2.6 million nmi 2 of ocean area, and includes designated Navy range complexes and associated operating areas (OPAREAs) and special use airspace. While the AFTT Study Area itself is very large, it is important to note that the vast majority of Navy training and testing occurs in designated range complexes and testing ranges. A Navy range complex consists of geographic areas that encompass a water component (above and below the surface) and airspace, and may encompass a land component where training and testing of military platforms, tactics, munitions, explosives, and electronic warfare systems occur. Range complexes include established OPAREAs, which may be further divided to provide better control of the area for safety reasons. Please refer to the regional maps provided in the Navy's rulemaking/LOA application (Figure 2.2-1 through Figure 2.2-3) for additional detail of the range complexes and testing ranges. Additional detail on range complexes and testing ranges was provided in our Federal Register notice of proposed rulemaking (83 FR 10954; March 13, 2018); please see that proposed rule or the Navy's application for more information. Comments and Responses We published a notice of proposed regulations in the Federal Register on March 13, 2018 (83 FR 10954), with a 45-day comment period. In that proposed rule, we requested public input on the request for authorization described therein, our analyses, and the proposed authorizations and requested that interested persons submit relevant information, suggestions, and comments. During the 45-day comment period, we received 28 total comment letters. Of this total, one submission was from another federal agency, two letters were from organizations or individuals acting in an official capacity ( e.g., non-governmental organizations (NGOs)) and 25 submissions were from private citizens. Letters from other NGOs and state departments that were received during the NOR were also considered further. NMFS has reviewed all public comments received on the proposed rule and issuance of the LOAs. All relevant comments and our responses are described below. We provide no response to specific comments that addressed species or statutes not relevant to our proposed actions under section 101(a)(5)(A) of the MMPA ( e.g., comments related to sea turtles). We outline our comment responses by major categories. General Comments The majority of the 25 comment letters from private citizens expressed general opposition toward the Navy's proposed training and testing activities and requested that NMFS not issue the LOAs, but without providing information relevant to NMFS' decisions. These comments appear to indicate a lack of understanding of the MMPA's requirement that NMFS “shall issue” requested authorizations when certain findings (see the Background section) are met; therefore, these comments were not considered further. The remaining comments are addressed below. Impact Analysis General Comment 1: A Commenter recommends that NMFS consult with the Navy to collect more information regarding the number, nature, and timing of testing and training events that take place within, or within close proximity to, important habitat areas, essentially refining the scale of the analysis of training and testing activities to match the scale of the habitat areas considered to be important. Response: In their take request and effects analysis provided to NMFS, the Navy considered historic use (number and nature of training and testing activities) and locational information of training and testing activities when developing modelling boxes. The timing of training cycles and testing needs varies based on deployment requirements to meet current and emerging threats. Due to the variability, the Navy's description of their specified activities is structured to provide flexibility in training and testing locations, timing, and number. In addition, information regarding the exact location of sonar usage is classified. Due to the variety of factors, many of which influence locations that cannot be predicted in advance ( e.g., weather), the analysis is completed at a scale that is necessary to allow for flexibility. The purpose of the Navy's quantitative acoustic analysis is to provide the best estimate of impact/take to marine mammals and ESA listed species for the regulatory and ESA section 7 consultation analyses. Specifically, the analysis must take into account multiple Navy training and testing activities over large areas of the ocean for multiple years; therefore, analyzing activities in multiple locations over multiple seasons produces the best estimate of impacts/take to inform the AFTT FEIS/OEIS and regulators. Also, the scale at which spatially explicit marine mammal density models are structured is determined by the data collection method and the environmental variables that are used to build the model. Therefore, altogether, given the variables that determine when and where the Navy trains and tests, as well as the resolution of the density data, the analysis of potential impacts is scaled to the level that the data fidelity will support. NMFS has worked with the Navy over the years to increase the spatio-temporal specificity of the descriptions of activities planned in or near areas of biological importance, when possible ( i.e., in NARW ESA-designated critical habitat), and NMFS is confident that the granularity of information provided sufficiently allows for an accurate assessment of both the impacts of the Navy's activities on marine mammal populations and the protective measures evaluated to mitigate those impacts. Density Estimates Comment 2: A Commenter noted that 30 iterations or Monte Carlo simulations is low for general bootstrapping methods used in those models but understands that increasing the number of iterations in turn increases the computational time needed to run the models. Accordingly, the Commenter suggests that the Navy consider increasing the iterations from 30 to at least 200 for activities that have yet to be modeled for Phase III and for all activities in Phase IV. Response: The 30 iterations used in NAEMO represent the number of iterations run for each of the four seasons analyzed in AFTT Phase III, which results in a total of 120 iterations per year for each event analyzed. For other areas where only warm and cold seasons are analyzed, the number of iterations per season is increased to 60 so that the same 120 iterations per year are maintained. Navy reached this number of iterations by running two iterations of a scenario and calculating the mean of exposures, then running a third iteration and calculating the running mean of exposures, then a fourth iteration and so on. This is done until the running mean becomes stable. Through this approach, it was determined 120 iterations was sufficient to converge to a statistically valid answer and provides a reasonable uniformity of exposure predictions for most species and areas. There are a few exceptions for species with sparsely populated distributions or highly variable distributions. In these cases, the running mean may not flatten out (or become stable); however, there were so few exposures in these cases that while the mean may fluctuate, the overall number of exposures did not result in significant differences in the totals. In total, the number of simulations conducted for AFTT Phase III exceeded six million simulations and produced hundreds of terabytes of data. Increasing the number of iterations, based on the discussion above, would not result in a significant change in the results, but would incur a significant increase in resources ( e.g., computational and storage requirements). This would divert these resources from conducting other more consequential analysis without providing for meaningfully improved data. The Navy has communicated that it is continually looking at ways to improve NAEMO and reduce data and computational requirements. As technologies and computational efficiencies improve, Navy will evaluate these advances and incorporate them where appropriate. Comment 3: A Commenter recommends that the Navy (1) specify what modeling method and underlying assumptions were used to estimate PTS and TTS zones for pile driving activities and (2) accumulate energy for the entire day of proposed activities, and (3) clarify why those zones were estimated to be the same for LF and HF. Response: The Navy has explained that it used measured values for source levels and transmission loss from pile driving of the Elevated Causeway System, the only pile driving activity included in the Proposed Action of the AFTT FEIS/OEIS. These recorded source waveforms were weighted using the auditory weighting functions. Low-frequency and high-frequency cetaceans have similar ranges for impact pile driving since low-frequency cetaceans would be relatively more sensitive to the low-frequency sound, which is below high-frequency cetaceans best range of hearing. Neither the NMFS user spreadsheet nor NAEMO were required for calculations. An area density model was developed in MS Excel, which calculated zones of influence to thresholds of interest ( e.g., behavioral response) based on durations of pile driving and the aforementioned measured and weighted source level values. The resulting area was then multiplied by density of each marine mammal species that could occur within the vicinity. This produced an estimated number of animals that could be impacted per pile, per day, and overall during the entire activity for both the impact pile driving and vibratory removal phases. Regarding the appropriateness of accumulating energy for the entire day, based on the best available science regarding animal reaction to sound, selecting a reasonable SEL calculation period is necessary to more accurately reflect the time period an animal would likely be exposed to the sound. The Navy factored both mitigation effectiveness and animal avoidance of higher sound levels into the impact pile driving analysis. For impact pile driving, the mitigation zone extends beyond the average ranges to PTS for all hearing groups; therefore, mitigation will help prevent or reduce the potential for exposure to PTS. The impact pile driving mitigation zone also extends beyond or into a portion of the average ranges to TTS; therefore, mitigation will help prevent or reduce the potential for exposure to all TTS or some higher levels of TTS, depending on the hearing group. Mitigation effectiveness and animal avoidance of higher sound levels were both factored into the impact pile driving analysis as most marine mammals should be able to easily move away from the expanding ensonified zone of TTS/PTS within 60 seconds, especially considering the soft start procedure, or avoid the zone altogether if they are outside of the immediate area upon startup. Marine mammals and sea turtles are likely to leave the immediate area of pile driving and extraction activities and be less likely to return as activities persist. However, some “naive” animals may enter the area during the short period of time when pile driving and extraction equipment is being re-positioned between piles. Therefore, an animal “refresh rate” of 10 percent was selected. This means that 10 percent of the single pile zone of influence (ZOI) was added for each consecutive pile within a given 24-hour period to generate the daily ZOI per effect category. These daily ZOIs were then multiplied by the number of days of pile driving and pile extraction and then summed to generate a total ZOI per effect category ( i.e., behavioral response, TTS, PTS). The small size of the mitigation zone and its close proximity to the observation platform will result in a high likelihood that Lookouts would be able to detect marine mammals and sea turtles throughout the mitigation zone. PTS/TTS Thresholds Comment 4: A Commenter supports the weighting functions and associated thresholds as stipulated in Finneran (2016), which are the same as those used for Navy Phase III activities, but points to additional recent studies that provide additional behavioral audiograms ( e.g., Branstetter et al., 2017, Kastelein et al., 2017b) and information on TTS ( e.g., Kastelein et al., 2017a; 2017c). However, the Commenter recommends that the Navy should provide a discussion of whether those new data corroborate the current weighting functions and associated thresholds. Response: The NMFS' revised Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2018), which was used in the assessment of effects for this action, compiled, interpreted, and synthesized the best available scientific information for noise-induced hearing effects for marine mammals to derive updated thresholds for assessing the impacts of noise on marine mammal hearing, including the articles that the Commenter references that were published subsequent to the publication of the first version of 2016 Acoustic Technical Guidance. The new data included in those articles are consistent with the thresholds and weighting functions included in the current version of the Acoustic Technical Guidance (NMFS 2018). NMFS will continue to review and evaluate new relevant data as it becomes available and consider the impacts of those studies on the Acoustic Technical Guidance to determine what revisions/updates may be appropriate. Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of this rule. Comment 5: A Commenter commented that the criteria that the agency has produced to estimate temporary threshold shift (TTS) and permanent threshold shift (PTS) in marine mammals are erroneous and non-conservative. The Commenter specifically cited many supposed issues with NMFS' Acoustic Technical Guidance, including adoption of “erroneous” models, broad extrapolation from a small number of individuals, and disregarding “non-linear accumulation of uncertainty.” The Commenter suggests that NMFS retain the historical 180-dB rms Level A harassment threshold as a “conservative upper bound” or conduct a “sensitivity analysis” to “understand the potential magnitude” of the supposed errors. Response: NMFS disagrees with this characterization of the Acoustic Technical Guidance and the associated recommendation. The Acoustic Technical Guidance is a compilation, interpretation, and synthesis of the scientific literature that provides the best available information regarding the effects of anthropogenic sound on marine mammals' hearing. The technical guidance was classified as a Highly Influential Scientific Assessment and, as such, underwent three independent peer reviews, at three different stages in its development, including a follow-up to one of the peer reviews, prior to its dissemination by NMFS. In addition, there were three separate public comment periods, during which time we received and responded to similar comments on the guidance (81 FR 51694), which we cross-reference here, and more recent public and interagency review under Executive Order 13795. The Acoustic Technical Guidance updates the historical 180-dB rms injury threshold, which was based on professional judgement ( i.e., no data were available on the effects of noise on marine mammal hearing at the time this original threshold was derived). NMFS does not believe the use of the Acoustic Technical Guidance provides erroneous results. The 180-dB rms threshold is plainly outdated, as the best available science indicates that rms SPL is not even an appropriate metric by which to gauge potential auditory injury (whereas the scientific debate regarding Level B behavioral harassment thresholds is not about the proper metric but rather the proper level or levels and how these may vary in different contexts). Multiple studies from humans, terrestrial mammals, and marine mammals have demonstrated less TTS from intermittent exposures compared to continuous exposures with the same total energy because hearing is known to experience some recovery in between noise exposures, which means that the effects of intermittent noise sources such as tactical sonars are likely overestimated. Marine mammal TTS data have also shown that, for two exposures with equal energy, the longer duration exposure tends to produce a larger amount of TTS. Most marine mammal TTS data have been obtained using exposure durations of tens of seconds up to an hour, much longer than the durations of many tactical sources (much less the continuous time that a marine mammal in the field would be exposed consecutively to those levels), further suggesting that the use of these TTS data are likely to overestimate the effects of sonars with shorter duration signals. Regarding the suggestion of pseudo-replication and erroneous models, since marine mammal hearing and noise-induced hearing loss data are limited, both in the number of species and in the number of individual's available, attempts to minimize pseudoreplication would further reduce these already limited data sets. Specifically, with marine mammal behavioral temporary threshold shift studies, behaviorally derived data are only available for two mid-frequency cetacean species (bottlenose dolphin, beluga) and two phocids (in-water) pinniped species (harbor seal and northern elephant seal), with otariid (in-water) pinnipeds and high-frequency cetaceans only having behaviorally-derived data from one species. Arguments from Wright (2015) regarding pseudoreplication within the TTS data are therefore largely irrelevant in a practical sense because there are so few data. Multiple data points were not included for the same individual at a single frequency. If multiple data existed at one frequency, the lowest TTS onset was always used. There is only a single frequency where TTS onset data exist for two individuals of the same species: 3 kHz for dolphins. Their TTS (unweighted) onset values were 193 and 194 dB re 1 μPa 2 s. Thus, NMFS believes that the current approach makes the best use of the given data. Appropriate means of reducing pseudoreplication may be considered in the future, if more data become available. Many other comments from Wright (2015) and the comments from Racca et al. (2015b) appear to be erroneously based on the idea that the shapes of the auditory weighting functions and TTS/PTS exposure thresholds are directly related to the audiograms; i.e., that changes to the composite audiograms would directly influence the TTS/PTS exposure functions ( e.g., Wright (2015) describes weighting functions as “effectively the mirror image of an audiogram” (p. 2) and states, “The underlying goal was to estimate how much a sound level needs to be above hearing threshold to induce TTS.” (p. 3)). Both statements are incorrect and suggest a fundamental misunderstanding of the criteria/threshold derivation. This would require a constant (frequency-independent) relationship between hearing threshold and TTS onset that is not reflected in the actual marine mammal TTS data. Attempts to create a “cautionary” outcome by artificially lowering the composite audiogram thresholds would not necessarily result in lower TTS/PTS exposure levels, since the exposure functions are to a large extent based on applying mathematical functions to fit the existing TTS data. Behavioral Harassment Thresholds Comment 6: A Commenter suggests that NMFS fails to set proper thresholds for behavioral impacts. Referencing the biphasic function that assumes an unmediated dose response relationship at higher received levels and a context-influenced response at lower received levels that NMFS uses to quantify Level B behavioral harassment from sonar, the Commenter suggests that resulting functions depend on some inappropriate assumptions that tend to significantly underestimate effects. The Commenter expresses concern that every data point that informs the agency's pinniped function, and nearly two-thirds of the data points informing the odontocete function (30/49), are derived from a captive animal study. Additionally, they assert that the risk functions do not incorporate (nor does NMFS apparently consider) a number of relevant studies on wild marine mammals. It is not clear from the proposed rule, or from the Navy's recent technical report on acoustic “criteria and thresholds,” on which NMFS' approach here is based, exactly how each of the studies that NMFS employed was applied in the analysis, or how the functions were fitted to the data, but the available evidence on behavioral response raises concerns that the functions are not conservative for some species. The Commenter recommends NMFS make additional technical information available, including from any expert elicitation and peer review, so that the public can fully comment. Response: The Criteria and Thresholds for U.S. Navy Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles technical report (U.S. Department of the Navy, 2017) details how the Navy's proposed method, which was determined appropriate and adopted by NMFS, accounted for the differences in captive and wild animals in the development of the behavioral response functions. The Navy uses the best available science, which has been reviewed by external scientists and approved by NMFS, in the analysis. The Navy and NMFS have utilized all available data that relate known or estimable received levels to observations of individual or group behavior as a result of sonar exposure (which is needed to inform the behavioral response function) for the development of updated thresholds. Limiting the data to the small number of field studies that include these necessary data would not provide enough data with which to develop the new risk functions. In addition, NMFS agrees with the assumptions made by the Navy to include the fact that captive animals may be less sensitive, in that the scale at which a moderate to severe response was considered to have occurred is different for captive animals than for wild animals, as the agency understands those responses will be different. The new risk functions were developed in 2016, before several recent papers were published or the data were available. As new science is published, the NMFS and the Navy continue to evaluate the information. The thresholds have been rigorously vetted among scientists and within the Navy community during expert elicitation and then reviewed by the public before being applied. It is unreasonable to revise and update the criteria and risk functions every time a new paper is published. These new and future papers provide additional information, and the Navy has already begun to consult them for updates to the thresholds in the future, when the next round of updated criteria will be developed. Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of the AFTT FEIS/OEIS or this rule. To be included in the behavioral response function, data sets need to relate known or estimable received levels to observations of individual or group behavior. Melcon et al. (2012) does not relate observations of individual/group behavior to known or estimable received levels (at that individual/group). In Melcon et al. (2012), received levels at the HARP buoy averaged over many hours are related to probabilities of D-calls, but the received level at the blue whale individuals/group are unknown. As noted, the derivation of the behavioral response functions is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). The appendices to this report detail the specific data points used to generate the behavioral response functions. Data points come from published data that is readily available and cited within the technical report. Comment 7: Commenters have concerns with the use of distance “cut-offs” in the Level B behavioral harassment thresholds, and the recommend that NMFS refrain from using cut-off distances in conjunction with the Bayesian BRFs and re-estimate the numbers of marine mammal takes based solely on the Bayesian BRFs. Response: The consideration of proximity (cut-off distances) was part of the criteria developed in consultation between Navy and NMFS and was applied within the Navy's acoustic effects model. Cut-off distances were used to better reflect the take potential for military readiness activities as defined in the MMPA. The derivation of the behavioral response functions and associated cut-off distances is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). Much of the data used to derive the behavioral response functions was from nearby, scaled sources, thereby potentially confounding results since it is difficult to tell whether the focal marine mammal is reacting to the sound level or the proximity of the source and/or vessel, amongst other potentially confounding contextual factors that are unlike actual Navy events for which the behavioral response functions (BRFs) are being derived. To account for these non-applicable contextual factors, all available data on marine mammal reactions to actual Navy activities and other sound sources (or other large scale activities such as seismic surveys when information on proximity to sonar sources is not available for a given species group, i.e., harbor porpoises) were reviewed to find the farthest distance to which significant behavioral reactions were observed. These distances were rounded up to the nearest 5 or 10 km interval, and for moderate to large scale activities using multiple or louder sonar sources, these distances were greatly increased — doubled in most cases. The Navy's BRFs applied within these distance is currently the best known method for providing the public and regulators with a more realistic (but still conservative where some uncertainties exist) estimate of impact and potential take under military readiness for the proposed actions within the AFTT FEIS/OEIS. NMFS has independently assessed the Navy's Level B behavioral harassment thresholds and believe that they appropriately apply the best available science and it is not necessary to recalculate take estimates. A Commenter also specifically expresses concern that distance “cut-offs” alleviate some of the exposures that would otherwise have been counted if the received level alone were considered. It is unclear why the Commenter finds this inherently inappropriate, as this is what the data show. As noted previously, there are multiple studies illustrating that in situations where one would expect a Level B behavioral harassment because of the received levels at which previous responses were observed, it has not occurred when the distance from the source was larger than the distance of the first observed response. Comment 8: Regarding cut-off distances, a Commenter further notes that dipping sonar appears a significant predictor of deep-dive rates in beaked whales on Southern California Anti-submarine Warfare Range (SOAR), with the dive rate falling significantly ( e.g., to 35 percent of that individual's control rate) during sonar exposure, and likewise appears associated with habitat abandonment. Importantly, these effects were observed at substantially greater distances ( e.g., 30 or more km) from dipping sonar than would otherwise be expected given the systems' source levels and the beaked whale response thresholds developed from research on hull-mounted sonar. They suggest that the analysis, and associated cut-off distances, do not properly consider the impacts of dipping sonar. Response: The Navy relied upon the best science that was available to develop the behavioral response functions in consultation with NMFS. The Navy's current beaked whale BRF acknowledges and incorporates the increased sensitivity observed in beaked whales during both behavioral response studies and during actual Navy training events, as well as the fact that dipping sonar can have greater effects than some other sources with the same source level. Specifically, the distance cut-off for beaked whales is 50 km, larger than any other group. Moreover, although dipping sonar has a significantly lower source level than hull-mounted sonar, it is included in the category of sources with larger distance cut-offs, specifically in acknowledgement of its unpredictability and association with observed effects. This means that “takes” are reflected at lower received levels that would have been excluded because of the distance for other source types. The referenced article ( Associating patterns in movement and diving behavior with sonar use during military training exercises: A case study using satellite tag data from Cuvier's beaked whales at the Southern California Anti-submarine Warfare Range (Falcone, 2015)) was not available at the time the behavioral response functions were developed. However, NMFS and the Navy have reviewed the article and concur that neither this article nor any other new information that has been published or otherwise conveyed would significantly change the assessment of impacts or conclusions in the AFTT FEIS/OEIS or in this rulemaking. Nonetheless, the new information and data presented in the new article were recently thoroughly reviewed by the Navy and will be quantitatively incorporated into future behavioral response functions, as appropriate. Comment 9: Regarding the behavioral thresholds for explosives, a Commenter recommends that NMFS estimate and ultimately authorize behavior takes of marine mammals during all explosive activities, including those that involve single detonations. Response: The derivation of the explosive injury criteria is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III), and NMFS has applied the general rule the Commenter references to single explosives for years, i.e., that marine mammals are unlikely to respond to a single instantaneous detonation in a manner that would rise to the level of a take. Neither NMFS nor the Navy are aware of evidence to support the assertion that animals will have significant behavioral reactions ( i.e., those that would rise to the level of a take) to temporally and spatially isolated explosions. The Navy has been monitoring detonations since the 1990's and has not observed these types of reactions. TTS and all other higher order impacts are assessed for all training and testing events that involve the use of explosives or explosive ordnance. All of Navy's monitoring projects, reports, and publications are available on the marine species monitoring web page ( https://www.navymarinespeciesmonitoring.us/ ). NMFS will continue to review applicable monitoring and science data and consider modifying these criteria when and if new information suggests it is appropriate. Mortality and Injury Thresholds for Explosions Comment 10: A Commenter recommends that NMFS require the Navy to (1) explain why the constants and exponents for onset mortality and onset slight lung injury thresholds for Phase III have been amended, (2) ensure that the modified equations are correct, and (3) specify any additional assumptions that were made. Response: The derivation of the explosive injury equations, including any assumptions, is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). It is our understanding that the constants and exponents for onset mortality and onset slight lung injury were amended by the Navy since Phase II to better account for the best available science. Specifically, the equations were modified in Phase III to fully incorporate the injury model in Goertner (1982), specifically to include lung compression with depth. The derivation of the Phase III equations and all associated assumptions are fully documented in the Navy's 2017 technical report Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). NMFS independently reviewed and concurred with this approach. Comment 11: A Commenter commented on circumstances of the deaths of multiple common dolphins during one of the Navy's underwater detonation events in March 2011 (Danil and St. Leger 2011) and indicated that the Navy's mitigation measures are not fully effective, especially for explosive activities. The Commenter believes it would be more prudent for the Navy to estimate injuries and mortalities based on onset rather than a 50-percent incidence of occurrence. The Navy did indicate that it is reasonable to assume for its impact analysis—thus its take estimation process—that extensive lung hemorrhage is a level of injury that would result in mortality for a wild animal (U.S. Department of the Navy 2017a). Thus, the Commenters notes that it is unclear why the Navy did not follow through with that premise. The Commenter recommends that NMFS use onset mortality, onset slight lung injury, and onset GI tract injury thresholds to estimate both the numbers of marine mammal takes and the respective ranges to effect. Response: Based on an extensive review of the incident referred to by the commenter, the Navy, in consultation with NMFS, revised and updated the mitigation for these types of events, which did not previously include consideration of the distance an animal could travel while the detonation was “delayed.” There have been no further incidents since these mitigation changes were instituted. The Navy used the range to one percent risk of mortality, as well as injury (referred to as “onset” in the AFTT DEIS/OEIS), to inform the development of mitigation ranges for explosions. In all cases, the proposed mitigation ranges for explosives extend beyond the range to one percent risk of non-auditory injury, even for a small animal (representative mass = 5 kg). In the AFTT FEIS/OEIS, the Navy clarified that the “onset” non-auditory injury and mortality criteria are actually one percent risk criteria. Over-predicting impacts, which would occur with the use of one percent non-auditory injury risk criteria in the quantitative analysis, would not afford extra protection to any animal. The Navy, in coordination with NMFS, has determined that the 50 percent incidence of occurrence is a reasonable mechanism for quantifying the likely effect, given the use of mitigation zones based on onset. Ranges to effect based on one percent risk criteria were examined to ensure that explosive mitigation zones would encompass the range to any potential mortality or non-auditory injury, affording actual protection against these effects. NMFS concurs with the Navy's approach for mitigating and quantifying injury and mortality from explosives. Although the commenter implies that the Navy did not use extensive lung hemorrhage as indicative of mortality, that statement is incorrect. Extensive lung hemorrhage is assumed to result in mortality, and the explosive mortality criteria are based on extensive lung injury data. See the technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). Range to Effects Comment 12: A Commenter notes an apparent error in Table 6.4-3 of the Navy's rulemaking/LOA application and recommends that NMFS determine what the appropriate ranges to TTS should be for bin LF5 and amend the ranges for the various functional hearing groups in the various tables accordingly. Response: The error in the table has been fixed; specifically, the ranges for MF cetaceans have been revised. Note that the distances are shorter than initially provided in proposed rule, indicating that the impacts of exposure to this bin are fewer than initially implied by the table. Regardless, the error was only associated with the information presented in this table; there was no associated error in any distances used in the take estimation, and both the take estimates and our findings remain the same. Comment 13: A Commenter recommends that the Navy use its spatially and temporally dynamic simulation models ( e.g., randomly-generated munition trajectories and animat simulations) rather than simple probability calculations to estimate strike probabilities and number of takes from expended munitions and non-explosive materials. Response: The recommendation of the Commenter to use a dynamic simulation model to estimate expended munitions and non-explosive materials strike probability was considered, but the Navy found, and NMFS agrees, that while the current analysis used in the AFTT FEIS/OEIS is more conservative and almost certainly over-estimates the potential impacts to marine mammals, it was preferable given the uncertainty involved in the prediction. An analysis of direct strike resulting from expended materials conducted in a dynamic simulation model such as NAEMO would also be a probability analysis; however, it would be conducted in a different manner. The current analysis provides an over-estimation of the probability of a strike for the following reasons: It (1) calculates the probability of a single military item (of all the items expended over the course of the year) hitting a single animal at its species' highest seasonal density; (2) does not take into account the possibility that an animal may avoid military activities; (3) does not take into account the possibility that an animal may not be at the water surface; (4) does not take into account that most projectiles fired during training and testing activities are fired at targets, and not all projectiles would hit the water with their maximum velocity and force; and (5) does not quantitatively take into account the Navy avoiding animals that are sighted through the implementation of mitigation measures. Given the uncertainty, and in order to be more conservative, NMFS and the Navy will continue using this method. Mitigation and Avoidance Calculations Comment 14: Commenters cite concerns that there was not enough information by which to evaluate the Navy's post-modeling calculations to account for mitigation and avoidance and imply that Level A harassment takes and mortality takes may be underestimated. A Commenter recommends that the Navy (1) provide the total numbers of model-estimated Level A harassment (PTS and slight lung and GI injuries) and mortality takes rather than reduce the estimated numbers of takes based on the Navy's post-model analyses and (2) include the model-estimated Level A harassment and mortality takes in its rulemaking/application to inform NMFS' negligible impact determination analyses. Response: The consideration of marine mammal avoidance and mitigation effectiveness is integral to the Navy's overall analysis of impacts from sonar and explosive sources. NMFS has independently evaluated the method and agrees that it is appropriately applied to augment the model in the prediction and authorization of injury and mortality as described in the rule. Details of this analysis are provided in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing. Sound levels diminish quickly below levels that could cause PTS. Studies have shown that all animals observed avoid areas well beyond these zones; therefore, the vast majority of animals are likely to avoid sound levels that could cause injury to their ear. As discussed in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing, animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way. The current best available science based on a growing body of behavioral response research shows that animals do in fact avoid the immediate area around sound sources to a distance of a few hundred meters or more depending upon the species. Avoidance to this distance greatly reduces the likelihood of impacts to hearing such as TTS and PTS. Specifically, behavioral response literature, including the recent 3S and SOCAL BRS studies, indicate that the multiple species from different cetacean suborders do in fact avoid approaching sound sources by a few hundred meters or more, which would reduce received sound levels for individual marine mammals to levels below those that could cause PTS. The ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases; however HF cetaceans such as harbor porpoises, have been observed reacting to anthropogenic sound at greater distances than other species and are likely to avoid their zones to hearing impacts (TTS and PTS) as well. As discussed in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing, the Navy's acoustic effects model does not consider procedural mitigations ( i.e., power-down or shut-down of sonars, or pausing explosive activities when animals are detected in specific zones adjacent to the source), which necessitates consideration of these factors in the Navy's overall acoustic analysis. Credit taken for mitigation effectiveness is extremely conservative. For example, if Lookouts can see the whole area, they get credit for it in the calculation; if they can see more than half the area, they get half credit; if they can see less than half the area, they get no credit. Not considering animal avoidance and mitigation effectiveness would lead to a great overestimate of injurious impacts. NMFS concurs with the analytical approach used. Last, the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing very clearly explains in detail how species sightability, the Lookout's ability to observe the range to PTS (for sonar and other transducers) and mortality (for explosives), the portion of time when mitigation could potentially be conducted during periods of reduced daytime visibility (to include inclement weather and high sea state) and the portion of time when mitigation could potentially be conducted at night, and the ability for sound sources to be positively controlled (powered down) are considered in the post-modeling calculation to account for mitigation and avoidance. It is not necessary to view the many tables of numbers generated in the assessment to evaluate the method. Comment 15: A Commenter stated in regards to the method in which the Navy's post-model calculation considers avoidance specifically ( i.e., assuming animals present beyond the range of PTS for the first few pings will be able to avoid it and incur only TTS), given that sound sources are moving, it may not be until later in an exercise that the animal is close enough to experience PTS, and it is those few close pings that contribute to the potential to experience PTS. An animal being beyond the PTS zone initially has no bearing on whether it will come within close range later during an exercise since both sources and animals are moving. In addition, Navy vessels may move faster than the ability of the animals to evacuate the area. The Navy should have been able to query the dosimeters of the animats to verify whether its five-percent assumption was valid. Response: The consideration of marine mammals avoiding the area immediately around the sound source is provided in the Navy's 2018 technical report titled Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles. As the Commenter correctly articulates: “For avoidance, the Navy assumed that animals present beyond the range to onset PTS for the first three to four pings are assumed to avoid any additional exposures at levels that could cause PTS. That equated to approximately five percent of the total pings or 5 percent of the overall time active; therefore, 95 percent of marine mammals predicted to experience PTS due to sonar and other transducers were instead assumed to experience TTS.” In regard to the comment about vessels moving faster than animals' ability to get out of the way, as discussed in the Navy's 2018 technical report titled Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles, animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way, necessitating the additional step of considering animal avoidance of close-in PTS zones. NMFS independently reviewed this approach and concurs that it is fully supported by the best available science. Based on a growing body of behavioral response research, animals do in fact avoid the immediate area around sound sources to a distance of a few hundred meters or more depending upon the species. Avoidance to this distance greatly reduces the likelihood of impacts to hearing such as TTS and PTS, respectively. Specifically, the ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases; however HF cetaceans such as harbor porpoises have been observed reacting to anthropogenic sound at greater distances than other species and are likely to avoid their zones to hearing impacts (TTS and PTS) as well. Querying the dosimeters of the animats would not produce useful information since, as discussed previously, the animats do not move in the horizontal and are not programmed to “react” to sound or any other stimulus. Comment 16: A Commenter asserted that the Navy's adjustment of injury and mortality numbers for “mitigation effectiveness” is also problematic. The analysis starts with species-specific g(0) factors (probability of detection of animals at zero distance) applied in professional marine mammal abundance surveys, then multiplies them by a simple factor to reflect the relative effectiveness of the Navy's Lookouts in routine operating conditions. Yet the Navy's sighting effectiveness is likely to be much poorer than that of experienced biologists dedicated exclusively to marine mammal detection, operating under conditions that maximize sightings. As one recent paper observed, for example, abundance survey rates declined significantly as sea states rose above Beaufort 1, and average Beaufort sea states in the mid- and southeast Atlantic average Beaufort 3-4 throughout the year (see Table 1). Given this, it seems that Navy visual surveys can seldom approximate the sighting effectiveness of a large-vessel abundance survey. Response: Information about the quantitative analysis process, including the consideration of mitigation effectiveness, is described in detail in the 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing. The Navy quantitatively assessed the effectiveness of its mitigation measures on a per-scenario basis using four factors: (1) Species sightability, (2) a Lookout's ability to observe the range to permanent threshold shift (for sonar and other transducers) and range to mortality (for explosives), (3) the portion of time when mitigation could potentially be conducted during periods of reduced daytime visibility (to include inclement weather and high sea-state) and the portion of time when mitigation could potentially be conducted at night, and (4) the ability for sound sources to be positively controlled ( e.g., powered down). The g(0) values used by the Navy for their mitigation effectiveness adjustments take into account the differences in sightability with sea state, and utilize averaged g(0) values for sea states of 1-4 and weighted as suggested by Barlow (2015). This helps to account for reduced sightability in varying conditions, as does the fact that, during active sonar activities, Navy Lookouts tend to look in the water near the vessel, within 1 km, rather than out to the horizon as Marine Mammal Observers (MMO) do. During training and testing activities, there is typically at least one, if not numerous, support personnel involved in the activity ( e.g., range support personnel aboard a torpedo retrieval boat or support aircraft). In addition to the Lookout posted for the purpose of mitigation, these additional personnel observe for and disseminate marine species sighting information amongst the units participating in the activity whenever possible as they conduct their primary mission responsibilities. However, as a conservative approach to assigning mitigation effectiveness factors, the Navy elected to account only for the minimum number of required Lookouts used for each activity; therefore, the mitigation effectiveness factors may underestimate the likelihood that some marine mammals (as well as sea turtles) may be detected during activities that are supported by additional personnel who may also be observing the mitigation zone. NMFS independently reviewed and concurs with this analysis. Comment 17: A Commenter comments on the potential for serious injury and mortality that could occur in the event of a ship strike or as a result of marine mammal exposure to explosive detonations (ship shock trials) and suggests that NMFS' prediction that only these few takes will result from Navy's thousands of hours of training and testing activities has misrepresented the science. Specifically, the Commenter discusses the risk of ship strike to NARW and suggested that it appears as a glaring omission from the list of species authorized for lethal take. While the Commenter concurred with NMFS' refusal to authorize a single ship strike to the NARW, they do not share the agency's level of confidence that the Navy will be able to effectively mitigate the potential for a ship strike to occur. They further suggest that NMFS has failed to consider the indirect effects of noise on ship-strike risk. They also assert that indirect ship strike risk resulting from habitat displacement must be accounted for in NMFS' analysis. The Commenter recommends additional mitigation measures slowing ships to 10 kn. Response: As described in greater detail in the Take from Vessel Strikes section of the final rule, although NMFS' analysis shows that NARWs have a low probability of being struck even one time within the five-year period of the rule when strikes across all activity types (including non-Navy) are considered (10.11 percent, lower than all other stocks except North Atlantic sperm whales), when the enhanced mitigation measures the Navy will implement for NARWs are considered in combination with this low probability, the Navy and NMFS have determined that a vessel strike is highly unlikely and, therefore, it was not requested and is not authorized. In addition to procedural mitigation, the Navy will limit MTEs and implement additional protective measures in mitigation areas used by NARW for foraging, calving, and migration (where individuals are concentrated and more likely to be struck). These measures, which go above and beyond those focused on other species ( e.g., funding of and communication with sightings systems, implementation of speed reductions during applicable circumstances in certain areas) have helped the Navy avoid striking a NARW during training and testing activities in the past; and eliminate the potential for future strikes to occur in the five years of the rule. In particular, the mitigation pertaining to communication among vessels, including the continued participation in and sponsoring of the Early Warning System (EWS, a comprehensive information exchange network dedicated to reducing the risk of vessel strikes to NARW in the Southeast) and NOAA's NARW Sighting Advisory System in the Northeast, will help Navy vessels avoid NARW during transits and training and testing activities. Implementation of these measures is expected to significantly reduce the probability of striking this particular species during the five-year period of the rule. Further, the Navy has agreed to expand the requirement for Navy vessels to contact the EWS from just the NARW ESA-designated critical habitat to the entire Jacksonville OPAREA. Additionally the Navy has developed a new mitigation measure to broadcast Dynamic Management Area information based on potential changes in NARW distribution. Platforms will use Dynamic Management Area information to assist their visual observation of applicable mitigation zones during training and testing activities. This will make units even more aware of NARW aggregations to better plan and conduct activities to minimize interactions with this species. Not only will this mitigation measure help the Navy further avoid or reduce potential impacts on NARW from vessel movements, it will also help aid the implementation of applicable procedural mitigation measures for acoustic, explosive, and physical disturbance and strike stressors when Dynamic Management Areas are in effect. Ship strikes are a fluke encounter for which the probability can never be zero for any vessel. However, the probability for any particular ship striking a marine mammal is primarily a product of the ability of the ship to detect a marine mammal and the ability to effectively act to avoid it. Navy combat ships are inherently among the best at both of these abilities because compared to large commercial vessels, they have trained Lookouts which have received specialized MMO training and the most maneuverable ships, which means that they are more likely to sight a marine mammal and more likely to be able to maneuver to avoid it in the available time—both of which decrease the probability of striking a marine mammal below what it would have been in the absence of those abilities. In the case of the NARW, the extensive communication/detection network described above, which is in use in the areas of highest NARW occurrence and where they may be more susceptible to strike, further increases the likelihood of detecting a NARW and thereby avoiding it, which further reduces the probability of NARW strike. Because of these additional mitigation measures combined with the already low probability that a NARW will be struck, it is extremely unlikely the Navy will strike a NARW and mortality/serious injury of a NARW from vessel strike is neither anticipated nor authorized. Regarding the likelihood of mortality from explosives, the Commenter does not offer any data or rationale to support the assertion that NMFS has underestimated the mortality from explosives. The analysis and estimates contained in the final rule are based on the best available science and accurately represent the appropriate take numbers for mortality and injury from explosives. Underestimated Beaked Whale Injury and Mortality Comment 18: A Commenter claims that NMFS is underestimating serious injury and mortality for beaked whales. They note the statement in the proposed rule that because a causal relationship between Navy MFAS use and beaked whale strandings has not been established in all instances, and that, in some cases, sonar was considered to be only one of several factors that, in aggregate, may have contributed to the stranding event, NMFS does “not expect strandings, serious injury, or mortality of beaked whales to occur as a result of training activities.” (83 FR 11084). This opinion is inconsistent with best available science and does not take into account the fact that the leading explanation for the mechanism of sonar-related injuries—that whales suffer from bubble growth in organs that is similar to decompression sickness, or “the bends” in human divers—has now been supported by numerous papers. At the same time, the commenter argues that NMFS fails to seriously acknowledge that sonar can seriously injure or kill marine mammals at distances well beyond those established for permanent hearing loss (83 FR 10999) and dismisses the risk of stranding and other mortality events (83 FR 11084) based on the argument that such effects can transpire only under the same set of circumstances that occurred during known sonar-related events—an assumption that is arbitrary and capricious. In conclusion, they argue that none of NMFS' assumptions regarding the expected lack of serious injury and mortality for beaked whales are supported by the record, and all lead to an underestimation of impacts. Response: The Commenter's characterization of NMFS' analysis is incorrect. NMFS does not disregard the fact that it is possible for naval activities using hull-mounted tactical sonar to contribute to the death of marine mammals in certain circumstances (that are not present in the AFTT Study Area) via strandings resulting from behaviorally mediated physiological impacts or other gas-related injuries. NMFS discusses these potential causes and outlines the few cases where active naval sonar (in the U.S. or, largely, elsewhere) has either potentially contributed to or (as with the Bahamas example) been more definitively causally linked with marine mammal strandings. As noted, there are a suite of factors that have been associated with these specific cases of strandings directly associated with sonar (steep bathymetry, multiple hull-mounted platforms using sonar simultaneously, constricted channels, strong surface ducts, etc.) that are not present together in the AFTT Study Area and during the specified activities (and which the Navy takes care across the world not to operate under without additional monitoring). Further, there have never been any strandings associated with Navy sonar use in the AFTT Study Area. For these reasons, NMFS does not anticipate that the Navy's AFTT training or testing activities will result in marine mammal strandings, and none are authorized. Ship Strike Comment 19: A Commenter asserted that the Navy's analysis, which NMFS used to support its vessel-strike analysis in the rule, does not address the potential for increased strike risk by non-Navy vessels as a consequence of acoustic disturbance. For example, some types of anthropogenic noise have been shown to induce near-surfacing behavior in NARW, increasing the risk of ship-strike at relatively moderate levels of exposure. An analysis based on reported strikes by Navy vessels does not account for this additional risk. In assessing ship-strike risk, the Navy should include offsets to account for potentially undetected and unreported collisions. Response: There is no evidence that Navy training and testing activities (or other acoustic activities) increase the risk of nearby non-Navy vessels (or other nearby Navy vessels not involved in the referenced training or testing) striking marine mammals. Further, any increase in the probability of hitting a NARW resulting from this speculated effect would already inherently be accounted for in the probability included in our analysis, which is based on the actual estimated number of NARW strikes (which accounts for unreported non-Navy vessel strikes). Lastly, the anthropogenic noise signal referred to in the comment was developed specifically to elicit a response from NARWs. This type of signal is not analogous to any sound source used by Navy. Comment 20: A Commenter asserts that NMFS and the Navy's analyses fail to account for the likelihood that the number of ship strikes are grossly underestimated because some animals are struck and not recovered or reported. Response: While NMFS agrees that broadly speaking the number of total ship strikes may be underestimated due to incomplete information from other sectors (shipping, etc.), NMFS is confident that whales struck by Navy vessels are detected and reported, and Navy strikes are the numbers used in NMFS' analysis to support the authorized number of strikes. Navy ships have multiple Lookouts, including on the forward part of the ship that can visually detect a hit whale (which has occasionally occurred), in the unlikely event ship personnel do not feel the strike. Navy's strict internal procedures and implementation of past mitigation measures require reporting of any vessel strikes of marine mammals and the Navy's discipline and chain of command give NMFS a high level of confidence that all strikes actually get reported. Accordingly, NMFS is confident that the information used to support the analysis is accurate and complete. Mitigation and Monitoring Least Practicable Adverse Impact Determination Comment 21: A Commenter comments that deaths of or serious injuries to marine mammals that occur pursuant to activities conducted under an incidental take authorization, while perhaps negligible to the overall health and productivity of the species or stock and of little consequence at that level, nevertheless are clearly adverse to the individuals involved and results in some quantifiable (though negligible) adverse impact on the population; it reduces the population to some degree. Under the least practicable adverse impact requirement, and more generally under the purposes and policies of the MMPA, the Commenter asserts that Congress embraced a policy to minimize, whenever practicable, the risk of killing or seriously injuring a marine mammal incidental to an activity subject to section 101(a)(5)(A), including providing measures in an authorization to eliminate or reduce the likelihood of lethal taking. The Commenter recommends that NMFS address this point explicitly in its analysis and clarify whether it agrees that the incidental serious injury or death of a marine mammal always should be considered an adverse impact for purposes of applying the least practicable adverse impact standard. Response: NMFS disagrees that it is necessary or helpful to explicitly address the point the Commenter raises in the general description of the LPAI standard. The discussion of this standard already notes that there can be population-level impacts that fall below the “negligible” standard, but that are still appropriate to mitigate under the LPAI standard. It is always NMFS' practice to mitigate mortality to the greatest degree possible, as death is the impact that is most easily linked to reducing the probability of adverse impacts to populations. However, we cannot agree that one mortality will always decrease any population in a quantifiable or meaningful way. For example, for very large populations, one mortality may fall well within typical known annual variation and not have any effect on population rates. Further, we do not understand the problem that the Commenter's recommendation is attempting to fix. Applicants generally do not express reluctance to mitigate mortality, and we believe that modifications of this nature would confuse the issue. Comment 22: A Commenter recommends that NMFS address the habitat component of the least practicable adverse impact provision in greater detail. It asserts that NMFS' discussion of ESA-designated critical habitat, marine sanctuaries, and BIAs in the proposed rule is not integrated with the discussion of the least practicable adverse impact standard. It would seem that, under the least practicable adverse impact provision, adverse impacts on important habitat should be avoided whenever practicable. Therefore, to the extent that activities would be allowed to proceed in these areas, NMFS should explain why it is not practicable to constrain them further. Response: Marine mammal habitat value is informed by marine mammal presence and use and, in some cases, there may be overlap in measures for the species or stock directly and for use of habitat. In this rule, we have identified time-area mitigations based on a combination of factors that include higher densities and observations of specific important behaviors of marine mammals themselves, but also that clearly reflect preferred habitat ( e.g., feeding areas in the Northeast, NARW calving areas in the Southeast). In addition to being delineated based on physical features that drive habitat function ( e.g., bathymetric features, among others for some BIAs), the high densities and concentration of certain important behaviors ( e.g., feeding) in these particular areas clearly indicate the presence of preferred habitat. The Commenter seems to suggest that NMFS must always consider separate measures aimed at marine mammal habitat; however, the MMPA does not specify that effects to habitat must be mitigated in separate measures, and NMFS has clearly identified measures that provide significant reduction of impacts to both “marine mammal species and stocks and their habitat,” as required by the statute. Comment 23: A Commenter recommends that NMFS rework its evaluation criteria for applying the least practicable adverse impact standard to separate the factors used to determine whether a potential impact on marine mammals or their habitat is adverse and whether possible mitigation measures would be effective. In this regard, the Commenter asserts that it seems as though the proposed “effectiveness” criterion more appropriately fits as an element of practicability and should be addressed under that prong of the analysis. In other words, a measure not expected to be effective should not be considered a practicable means of reducing impacts. Response: In the Mitigation Measures section, NMFS has explained in detail our interpretation of the LPAI standard, the rationale for our interpretation, and our approach for implementing our interpretation. The ability of a measure to reduce effects on marine mammals is entirely related to its “effectiveness” as a measure, whereas the effectiveness of a measure is not connected to its practicability. The Commenter provides no support for its argument, and NMFS has not implemented the Commenter's suggestion. Comment 24: A Commenter recommends that NMFS recast its conclusions to provide sufficient detail as to why additional measures either are not needed ( i.e., there are no remaining adverse impacts) or would not be practicable to implement. The Commenter states that the most concerning element of NMFS' implementation of the least practicable adverse impact standard is its suggestion that the mitigation measures proposed by the Navy will sufficiently reduce impacts on the affected mammal species and stocks and their habitats (83 FR 11045). That phrase suggests that NMFS is applying a “good-enough” standard to the Navy's activities. Under the statutory criteria, however, those proposed measures are “sufficient” only if they have either (1) eliminated all adverse impacts on marine mammal species and stocks and their habitat or (2) if adverse impacts remain, it is impracticable to reduce them further. Response: The statement that the Commenter references does not indicate that NMFS applies a “good-enough” standard to determining least practicable adverse impact. Rather, it indicates that the mitigation measures are sufficient to meet the statutory legal standard. In addition, as NMFS has explained in our description of the least practicable adverse impact standard, NMFS does not view the necessary analysis through the yes/no lens that the Commenter seeks to prescribe. Rather, NMFS' least practicable adverse impact analysis considers both the reduction of adverse effects and the practicability. Further, since the proposed rule was published, the Navy and NMFS have evaluated additional measures in the context of both their practicability and their ability to further reduce impacts to marine mammals and have determined that the addition of several measures (see Mitigation Measures ) is appropriate. Regardless, beyond these new additional measures, where the Navy's AFTT activities are concerned, the Navy has indicated that further procedural or area mitigation of any kind (beyond that prescribed in this final rule) would be entirely impracticable. Comment 25: A Commenter recommends that any “formal interpretation” of the least practicable adverse impact standard by NMFS be issued in a stand-alone, generally applicable rulemaking ( e.g., in amendments to 50 CFR 216.103 or 216.105) or in a separate policy directive, rather than in the preambles to individual proposed rules. Response: We appreciate the Commenter's recommendation and may consider the recommended approaches in the future. We note, however, that providing relevant explanations in a proposed incidental take rule is an effective and efficient way to provide information to the reader and solicit focused input from the public, and ultimately affords the same opportunities for public comment as a stand-alone rulemaking would. NMFS has provided similar explanations of the least practicable adverse impact standard in other recent section 101(a)(5)(A) rules, including: U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar; Geophysical Surveys Related to Oil and Gas Activities in the GOMEX; and the proposed rule for U.S. Navy Training and Testing in the Hawaii-Southern California Training and Testing (HSTT) Study Area. Comment 26: A Commenter cites two judicial decisions and comments that while there have been some improvements in mitigation relative to NMFS' 2013-2018 final rule for AFTT activities, the “least practicable adverse impact” standard has not been met. The Commenter asserts, for example, that if in prescribing protective measures in important habitat NMFS concludes after careful analysis that complete exclusion of unit-level sonar training from the area is not practicable, the agency should consider what reductions in activity are practicable, as by looking at particular types of exercises or testing activities or by limiting the amount of activity that can take place. The Commenter argues that the MMPA sets forth a “stringent standard” for mitigation that requires the agency to minimize impacts to the lowest practicable level, and that the agency must conduct its own analysis and clearly articulate it: it “cannot just parrot what the Navy says.” Response: NMFS disagrees with much of what the Commenter asserts. When a suggested or recommended mitigation measure is impracticable, NMFS has explored variations of that mitigation to determine if a practicable form of related mitigation exists. This is clearly illustrated in NMFS' independent mitigation analysis process explained in this rule. First, the type of mitigation required varies by mitigation area, demonstrating that NMFS has engaged in a site-specific analysis to ensure mitigation is tailored only when practicability demands, i.e., some forms of mitigation were practicable in some areas but not others. Other examples of NMFS' analysis on this issue appear throughout the rule. For instance, while it was not practicable for the Navy to expand the SE NARW Mitigation Area to the full extent recommended, the Navy did agree to some expansion of the SE NARW Mitigation Area to provide better protection. Additionally, while the Navy cannot alleviate all training in the NE NARW Mitigation Area due to changes in requirements, Navy removed one impactful testing activity (four events) that reduced takes for NARW and other species significantly. Nonetheless, NMFS agrees that the agency must conduct its own analysis, which it has done here, and not just accept w [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2018-24042. Public record. Not legal advice.