# Taking and Importing Marine Mammals: Taking Marine Mammals Incidental to U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active Sonar > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2017-08066 ## Record - **Collection:** Federal Register - **Document type:** Proposed Rule - **Published:** April 27, 2017 - **Citation:** 82 FR 19460 ## Text DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 218 [Docket No. 160920860-7368-01] RIN 0648-BG35 Taking and Importing Marine Mammals: Taking Marine Mammals Incidental to U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active Sonar AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Proposed rule; request for comments. SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for authorization to take marine mammals, by harassment, incidental to conducting operations of Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA) sonar in areas of the world's oceans (with the exception of Arctic and Antarctic waters and certain geographic restrictions), from August 15, 2017, through August 14, 2022. The Navy's activities are considered military readiness activities pursuant to the Marine Mammal Protection Act (MMPA), as amended by the National Defense Authorization Act for Fiscal Year 2004 (FY 2004 NDAA). Pursuant to the MMPA, NMFS is requesting comments on its proposal to issue regulations to govern the incidental take of marine mammals by Level B harassment during the specified activity. DATES: Comments and information must be received no later than May 30, 2017. ADDRESSES: You may submit comments on this document, identified by NOAA-HQ-2017-0037, by either of the following methods: Electronic Submission: Submit all electronic public comments via the Federal e-Rulemaking Portal. Go to www.regulations.gov/#!docketDetail;D=NOAA-HQ-2017-0037 , click the “Comment Now!” icon, complete the required fields, and enter or attach your comments. Mail: Comments should be addressed to Jolie Harrison, Chief, Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service. Physical comments should be sent to 1315 East-West Highway, Silver Spring, MD 20910. Instructions: NMFS is not responsible for comments sent by any other method, to any other address or individual, and may not consider comments received after the end of the comment period. Comments received electronically, including all attachments, must not exceed a 25-megabyte file size. Attachments to electronic comments will be accepted in Microsoft Word, Excel, or Adobe PDF formats only. To help NMFS process and review comments more efficiently, please use only one method to submit comments. All comments received are a part of the public record and will generally be posted to www.regulations.gov and www.nmfs.noaa.gov/pr/permits/incidental/military without change. All Personal Identifying Information (for example, name, address, etc.) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business Information or otherwise sensitive or protected information. FOR FURTHER INFORMATION CONTACT: Dale Youngkin, Office of Protected Resources, NMFS, (301) 427-8401. Electronic copies of the application and supporting documents, as well as a list of the references cited in this document, may be obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/military.htm . In case of problems accessing these documents, please call the contact listed above. SUPPLEMENTARY INFORMATION: Background Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1361 et seq. ) directs the Secretary of Commerce (Secretary) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals in a specified geographical region for a period of up to five years, provided that certain findings are made and the necessary prescriptions are established. The incidental taking of marine mammals shall be allowed if NMFS (through authority delegated by the Secretary) finds that the total taking by the specified activity during the specified time period will (1) have a negligible impact on the species or stock(s) and (2) not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant). Further, the permissible methods of taking and other means of effecting the least practicable adverse impact on the species or stock and its habitat ( i.e., mitigation) must be prescribed. Requirements pertaining to the monitoring and reporting of such taking must also be set forth. The allowance of incidental taking under section 101(a)(5)(A) requires promulgation of activity specific regulations. Subsequently, a Letter (or Letters) of Authorization (LOA) may be issued as governed by the regulations, provided that the level of taking will be consistent with the findings made for the total taking allowable under the specific regulations. The promulgation of regulations (with their associated prescribed mitigation, monitoring, and reporting) requires notice and opportunity for public comment. NMFS has defined “Negligible impact” in 50 CFR 216.103 as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival. The National Defense Authorization Act for Fiscal Year 2004 (FY 2004 NDAA) (Pub. L. 108-136) removed the “small numbers” and “specified geographical region” limitations indicated above and amended the definition of “harassment” as it applies to a “military readiness activity” to read as follows (Section 3(18)(B) of the MMPA): “(i) any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild” (Level A Harassment); “or (ii) any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including but not limited to migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered” (Level B Harassment). In addition, the FY 2004 NDAA amended the MMPA as it relates to military readiness activities and the Incidental Take Authorization (ITA) process such that “least practicable adverse impact” shall include consideration of personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. Summary of Request On August 26, 2016, NMFS received an application from the Navy requesting authorization for the take of individuals of 104 currently classified species or stocks of marine mammals (15 species of mysticete (baleen) whales, 60 species of odontocete (toothed) whales, and 29 species of pinnipeds (seals and sea lions)), by harassment, incidental to the use of SURTASS LFA sonar on a maximum of four U.S. Naval ships for routine training, testing, and military operations, hereafter called activities, in various areas of the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea from August 15, 2017 through August 14, 2022. These activities are classified as military readiness activities. The Navy states, and NMFS concurs, that these military readiness activities may incidentally take marine mammals present within the Navy's operation areas by exposing them to SURTASS LFA sonar at levels that constitute Level B harassment as defined above. The Navy requests authorization to take individuals of the 104 currently classified species or stocks of marine mammals by Level B Harassment. This rule may also cover the authorization of additional associated stocks of marine mammals not listed here, should one or more of the stocks identified in this rule be formally separated into multiple stocks, provided NMFS is able to confirm the necessary findings for the newly identified stocks. As discussed later in this document, takes due to SURTASS LFA sonar will be limited to Level B behavioral harassment. No takes by Level A harassment will be authorized as Level A harassment will be avoided through the implementation of the Navy's proposed mitigation measures. In previous rulemakings, NMFS authorized small numbers of Level A takes out of an abundance of caution even though Level A takes were not anticipated. However, there have been no Level A takes resulting from the past 14 years of SURTASS LFA sonar activities under previous rules. Additionally, the criteria and thresholds for assessing Level A harassment have been modified since prior rules. Under the new metrics, the potential for injury zone has been substantially reduced. Therefore, due to the small injury zones and the fact that mitigation measures would ensure that marine mammals would not receive levels associated with injury, the Navy has not requested authorization for Level A harassment takes, and NMFS is not proposing to authorize any takes by Level A harassment. This is NMFS' fourth rulemaking for SURTASS LFA sonar activities under the MMPA. NMFS' current five-year regulations governing incidental takings incidental to SURTASS LFA sonar activities and the related Letters of Authorizations (LOA) expire on August 15, 2017. NMFS published the first SURTASS LFA sonar rule on July 16, 2002 (67 FR 46712), effective from August 2002 through August 2007. The second rule was published on August 21, 2007 (72 FR 46846), effective from August 16, 2007, through August 15, 2012. The third rule was published on August 20, 2012 (77 FR 50290), and is effective through August 14, 2017. For this proposed rulemaking, the Navy proposes to conduct the same types of sonar activities as they have conducted over the past 14 years with the following exception: The Navy proposes to transmit a maximum number of 255 hours of LFA sonar per vessel per year, as opposed to the previously authorized 432 hours of LFA sonar per vessel per year. Based on historical operating parameters, the average duty cycle ( i.e., the ratio of sound “on” time to total time) for SURTASS LFA sonar is normally 7.5 to 10 percent and the duty cycle is not expected to exceed 20 percent. Description of the Specified Activities Overview The proposed action is Navy's continued employment of up to four SURTASS LFA sonar systems in the world's non-polar oceans, which is classified as a military readiness activity, from August 2017 to August 2022. Potential activities could occur in the Pacific, Atlantic, and Indian Oceans, and the Mediterranean Sea. The Navy will not operate SURTASS LFA sonar in Arctic and Antarctic waters. Additional geographic restrictions include maintaining SURTASS LFA sonar received levels below 180 dB re 1 µPa (root-mean-square (rms)) within 12 nautical miles (nmi) (22 kilometers (km)) of any land, and within the boundaries of designated Offshore Biologically Important Areas (OBIAs) during their effective periods (see below for more OBIA details). Purpose and Background The Navy's primary mission is to maintain, train, equip, and operate combat-ready naval forces capable of accomplishing American strategic objectives, deterring maritime aggression, and assuring freedom of navigation in ocean areas. This mission is mandated by Federal law in Section 5062 of Title 10 of the United States Code, which directs the Secretary of the Navy and Chief of Naval Operations (CNO) to ensure the readiness of the U.S. naval forces. The Secretary of the Navy and the CNO have established that anti-submarine warfare (ASW) is a critical capability for achieving the Navy's mission, and it requires unfettered access to both the high seas and littoral environments to be prepared for all potential threats by maintaining ASW core competency. The Navy is challenged by the increased difficulty in locating undersea threats solely by using passive acoustic technologies due to the advancement and use of quieting technologies in diesel-electric and nuclear submarines. At the same time as the distance at which submarine threats can be detected decreases due to quieting technologies, improvements in torpedo and missile design have extended the effective range of these weapons. One of the ways the Navy has addressed the changing requirements for ASW readiness was by developing SURTASS LFA sonar, which is able to reliably detect quieter and harder-to-find submarines at long range before these vessels can get within their effective weapons range to launch against their targets. SURTASS LFA sonar systems have a passive component (SURTASS), which is a towed line array of hydrophones used to detect sound emitted or reflected from submerged targets, and an active component (LFA), which is comprised of a set of acoustic transmitting elements. The active component detects objects by creating a sound pulse, or “ping” that is transmitted through the water and reflects off the target, returning in the form of an echo similar to echolocation used by some marine mammals to locate prey and navigate. SURTASS LFA sonar systems are long-range sensors that operate in the low-frequency (LF) band ( i.e., 100-500 Hertz (Hz)). Because LF sound travels in seawater for greater distances than higher frequency sound, the SURTASS LFA sonar system would meet the need for improved detection and tracking of new-generation submarines at a longer range and would maximize the opportunity for U.S. armed forces to safely react to, and defend against, potential submarine threats while remaining a safe distance beyond a submarine's effective weapons range. Thus, the active acoustic component in the SURTASS LFA sonar is an important augmentation to its passive and tactical systems, as its long-range detection capabilities can effectively counter the threat to the Navy and national security interests posed by quiet, diesel submarines. Dates and Duration Due to uncertainties in the world's political climate, a detailed account of future operating locations and conditions for SURTASS LFA sonar use over the next five years cannot be predicted. However, for analytical purposes, a nominal annual deployment schedule and operational concept were developed based on actual SURTASS LFA sonar activities conducted since January 2003 and projected Fleet requirements (See Table 1). Table 1—Example Annual Deployment Schedule for One Surveillance Vessel Using SURTASS LFA Sonar On mission Days Off mission Days Transit 54 In-Port Upkeep 40 Active Activities (Up to 255 transmission hours based on a nominal 7.5% duty cycle) 240 Regular Overhaul 31 Total Days on Mission 294 Total Days off Mission 71 Annually, each vessel is expected to spend approximately 54 days in transit and 294 days at sea conducting military readiness activities, which includes 240 days of active operations (amounting to 255 transmission hours based on a 7.5% duty cycle). Between missions, an estimated total of 71 days per year will be spent in port for upkeep and repair to maintain both the material condition of the vessel and its systems. The actual number and length of the individual missions within the 240 days are difficult to predict, but the maximum number of actual transmission hours per vessel per year will not exceed 255 hours. As noted above, this would be the fourth continuous such authorization for the Navy's SURTASS LFA sonar activities. The Navy's current rule and LOA expire after August 14, 2017. Therefore, the Navy has requested MMPA rulemaking and will request annual LOAs for its SURTASS LFA sonar activities effective from August 15, 2017 through August 14, 2022, to take marine mammals incidental to the activities of up to four SURTASS LFA sonar systems. Subsequent LOA applications would be submitted annually throughout the remaining years of the new rule. Potential SURTASS LFA Sonar Operational Areas Figure 1 depicts the potential areas of activities for SURTASS LFA sonar. In areas within 12 nmi from any shorelines (coastal exclusion areas) and in areas identified as OBIAs, SURTASS LFA sonar would be operated such that received levels of LFA sonar are below 180 dB re 1 μPa rms sound pressure level (SPL). This restriction would be observed year-round for coastal exclusion areas and during periods of biological importance for OBIAs, but these areas are not depicted in Figure 1 as these areas are not visible at the map scale. Based on the Navy's current operational requirements, potential activities for SURTASS LFA sonar vessels from August 2017 through August 2022 would include areas located in the Pacific, Atlantic, and Indian Oceans as well as the Mediterranean Sea. EP27AP17.000 The Navy will not operate SURTASS LFA sonar pursuant to this rule in polar regions ( i.e., Arctic and Antarctic waters) of the world (see shaded areas in Figure 1). The Arctic Ocean, the Bering Sea (including Bristol Bay and Norton Sound), portions of the Norwegian, Greenland, and Barents Seas north of 72° North (N) latitude, plus Baffin Bay, Hudson Bay, and the Gulf of St. Lawrence would be non-operational areas for SURTASS LFA sonar. In the Antarctic, the Navy will not conduct SURTASS LFA activities in areas south of 60° South (S) latitude. The Navy has excluded polar waters from operational planning because of the inherent inclement weather conditions and the navigational and operational (equipment) danger that icebergs pose to SURTASS LFA sonar vessels. The Navy must anticipate, or predict, where they have to operate in the next five years for the MMPA rulemaking. Naval forces are presently operating in several areas strategic to U.S. national and international interests. National security needs may dictate that many of these operational areas will be close to ports and choke points, such as entrances to straits, channels, and canals. It is anticipated that many future naval conflicts are likely to occur within littoral or coastal areas. However, it is infeasible for the Navy to analyze all potential global mission areas for all species and stocks for all seasons. Instead, the Navy projects where it intends to use SURTASS LFA sonar for the next five-year authorization period based on today's political climate and provides NMFS with take estimates for marine mammal stocks in the proposed areas of activity. NMFS believes that this provides sufficient coverage for worldwide SURTASS LFA sonar activities, as specific take numbers are requested on an annual basis in applications for LOAs, subject to an annual cap of 12 percent per stock. For this fourth rulemaking, the Navy modeled and analyzed 26 representative mission areas in the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea to represent the acoustic regimes and marine mammal species/stocks that may be encountered during worldwide SURTASS LFA sonar activities (see Table 2). They are comprised of the following modeled areas: East of Japan; north Philippine Sea; west Philippine Sea; offshore Guam; Sea of Japan; East China Sea; South China Sea; Offshore Japan (two locations: 25° to 40° N and 10° to 25° N); Hawaii North; Hawaii South; Offshore Southern California; western north Atlantic; eastern North Atlantic; Mediterranean Sea; Arabian Sea; Andaman Sea; Panama Canal; northeast Australia; northwest Australia; northeast of Japan; southern Gulf of Alaska; southern Norwegian Basin (between Iceland and Norway); western North Atlantic (off of Virginia/Maryland); Labrador Sea; and Sea of Okhotsk. Since the Navy cannot forecast the location of its operations, annual requests will be submitted to NMFS that will include specific mission areas and modeling locations for each year's activities. For more details of the impact analysis, see Appendix B in the DSEIS/SOEIS. Table 2—Potential SURTASS LFA Sonar Activity Areas That the Navy Modeled for the DSEIS/OEIS (DoN, 2016 a ) and the MMPA Rulemaking/LOA Application Modeled site Location (latitude/longitude of center of modeling area) Modeled site Location (latitude/longitude of center of modeling area) East of Japan 38° N., 148° E. Eastern North Atlantic 56.4° N., 10° W. North Philippine Sea 29° N., 136° E. Mediterranean Sea 39° N., 6° E. West Philippine Sea 22° N., 124° E. Arabian Sea 14°N., 65° E. Offshore Guam (Mariana Islands Range Complex, outside Mariana Trench) 11° N., 145° E. Andaman Sea 7.5° N., 96° E. Sea of Japan 39° N., 132° E. Panama Canal 5° N., 81° W. East China Sea 26° N., 125° E. Northeast Australia 23° S., 155° E. South China Sea 14° N., 114° E. Northwest Australia 18° S., 110° E. Offshore Japan 25° to 40° N 30° N., 165° E. Northeast of Japan 52° N., 163° E. Offshore Japan 10° to 25° N 15° N., 165° E. Southern Gulf of Alaska 51° N., 150° W. Hawai'i North 25° N., 158° W. Southern Norwegian Basin (between Iceland and Norway) 65° N., 0° Hawaii South 19.5° N., 158.5° W. Western North Atlantic (off of Virginia/Maryland) 39.6° N., 71.6° W. Offshore Southern California 32° N., 120° W. Labrador Sea 57° N., 50° W. Western North Atlantic (off Florida) 29° N., 76° W. Sea of Okhotsk 51° N., 150° E. The use of the SURTASS LFA sonar system during at-sea activities would result in acoustic stimuli from the generation of sound or pressure waves in the water at or above levels that NMFS has determined would result in take of marine mammals under the MMPA. This is the principal means of marine mammal taking associated with these military readiness activities and the Navy has requested authorization to take marine mammals by Level B harassment. At no point are there expected to be more than four systems in use, and thus this proposed rule analyzes the impacts on marine mammals due to the deployment of up to four SURTASS LFA sonar systems for a five-year period between August 2017 and August 2022. In addition to the use of active acoustic sources, the Navy's activities include the operation and movement of vessels. This document also analyzes the effects of this aspect of the activities. However, NMFS does not anticipate takes of marine mammals to result from ship strikes from any of the four SURTASS LFA vessels because each vessel moves at a relatively slow speed, especially when towing the SURTASS and LFA sonar systems, and for a relatively short period of time. Combined with the use of mitigation measures as noted below, it is likely that any marine mammal would be able to avoid the surveillance vessels. Detailed Description of the Specified Activities Description of SURTASS LFA Sonar SONAR is an acronym for Sound Navigation and Ranging, and its definition includes any system (biological or mechanical) that uses underwater sound, or acoustics, for detection, monitoring, and/or communications. Active sonar is the transmission of sound energy for the purpose of sensing the environment by interpreting features of received signals. Active sonar detects objects by creating a sound pulse, or “ping” that is transmitted through the water and reflects off the target, returning in the form of an echo. Passive sonar detects the transmission of sound waves created by an object. As mentioned previously, the SURTASS LFA sonar system is a long-range, all-weather LF sonar (operating between 100 and 500 Hertz (Hz)) system that has both active and passive components. LFA, the active system component (which allows for the detection of an object that is not generating noise), is comprised of source elements (called projectors) suspended vertically on a cable beneath the surveillance vessel. The projectors produce an active sound pulse by converting electrical energy to mechanical energy by setting up vibrations or pressure disturbances within the water to produce a ping. The Navy uses LFA as an augmentation to the passive SURTASS operations when passive system performance is inadequate. SURTASS, the passive part of the system, uses hydrophones ( i.e., underwater microphones) to detect sound emitted or reflected from submerged targets, such as submarines. The SURTASS hydrophones are mounted on a horizontal line array that is towed behind the surveillance vessel. The Navy processes and evaluates the returning signals or echoes, which are usually below background or ambient sound level, to identify and classify potential underwater targets. LFA Active Component The active component of the SURTASS LFA sonar system consists of up to 18 projectors suspended beneath the surveillance vessel in a vertical line array. The SURTASS LFA sonar projectors transmit in the low-frequency band (between 100 and 500 Hz). The source level of an individual projector in the SURTASS LFA sonar array is approximately 215 dB re: 1 μPa at 1 m or less (Sound pressure is the sound force per unit area and is usually measured in micropascals (μPa), where one Pascal (Pa) is the pressure resulting from a force of one newton exerted over an area of one square meter. The commonly used reference pressure level in underwater acoustics is 1 μPa at 1 m, and the units for source level are decibels (dB) re: 1 μPa at 1 m). Because of the physics involved in acoustic beamforming ( i.e., a method of mapping noise sources by differentiating sound levels based upon the direction from which they originate) and sound transmission loss processes, the SURTASS LFA sonar array cannot have a SPL higher than the SPL of an individual projector. The SURTASS LFA sonar acoustic transmission is an omnidirectional beam (a full 360 degrees (°)) in the horizontal plane. The LFA sonar system also has a narrow vertical beam that the vessel's crew can steer above or below the horizontal plane. The typical SURTASS LFA sonar signal is not a constant tone, but rather a transmission of various signal types that vary in frequency and duration (including continuous wave (CW) and frequency-modulated (FM) signals). A complete sequence of sound transmissions, also referred to by the Navy as a “ping” or a wavetrain, can be as short as six seconds (sec) or last as long as 100 sec, with an average length of 60 sec. Within each ping, the duration of any continuous frequency sound transmission is no longer than 10 sec and the time between pings is typically from six to 15 minutes (min). Based on the Navy's historical operating parameters, the average duty cycle ( i.e., the ratio of sound “on” time to total time) for LFA sonar is normally 7.5 to 10 percent and the duty cycle is not expected to exceed 20 percent. Compact LFA Active Component In addition to the LFA sonar system deployed on the USNS IMPECCABLE, the Navy developed a compact LFA (CLFA) sonar system now deployed on its three smaller surveillance vessels ( i.e., the USNS ABLE, EFFECTIVE, and VICTORIOUS). In the application, the Navy indicates that the operational characteristics of the active component CLFA sonar are comparable to the existing LFA systems and that the potential impacts from CLFA will be similar to the effects from the existing LFA sonar system. The CLFA sonar system consists of smaller projectors that weigh 142,000 lbs (64,410 kilograms (kg)), which is 182,000 lbs (82,554 kg) less that the mission weight of the LFA projectors on the USNS IMPECCABLE. The CLFA sonar system also consists of up to 18 projectors suspended beneath the surveillance vessel in a vertical line array and the CLFA sonar projectors transmit in the low-frequency band (also between 100 and 500 Hz) with the same duty cycle as described for LFA sonar. Similar to the active component of the LFA sonar system, the source level of an individual projector in the CLFA sonar array is approximately 215 dB re: 1 μPa or less. For the analysis in this rulemaking, NMFS will use the term LFA to refer to both the LFA sonar system and/or the CLFA sonar system, unless otherwise specified. SURTASS Passive Component The passive component of the SURTASS LFA sonar system consists of a SURTASS Twin-line (TL-29A) horizontal line array mounted with hydrophones. The Y-shaped array is 1,000 ft (305 m) in length and has an operational depth of 500 to 1,500 ft (152.4 to 457.2 m). The SURTASS LFA sonar vessel typically maintains a speed of at least 3.4 mph (5.6 km/hr; 3 knots (kts)) to tow the array astern of the vessel in the correct horizontal configuration. High-Frequency Active Sonar Although technically not part of the SURTASS LFA sonar system, the Navy also proposes to use a high-frequency sonar system, called the High Frequency Marine Mammal Monitoring sonar (HF/M3 sonar), to detect and locate marine mammals within the SURTASS LFA sonar activity areas and mitigation and buffer zones, as described later in this proposed rule. This enhanced commercial fish-finding sonar, mounted at the top of the SURTASS LFA sonar vertical line array, has a source level of 220 dB re: 1 μPa at 1 m with a frequency range from 30 to 40 kilohertz (kHz). The duty cycle is variable, but is normally below three to four percent and the maximum pulse duration is 40 milliseconds. The HF/M3 sonar has four transducers with 8° horizontal and 10° vertical beamwidths, which sweep a full 360° in the horizontal plane every 45 to 60 sec with a maximum range of approximately 1.2 mi (2 km). Vessel Specifications The Navy proposes to deploy the SURTASS LFA sonar system on a maximum of four U.S. Naval ships: the USNS ABLE (T-AGOS 20), the USNS EFFECTIVE (T-AGOS 21), the USNS IMPECCABLE (T-AGOS 23) and the USNS VICTORIOUS (T-AGOS 19). The USNS ABLE, EFFECTIVE, and VICTORIOUS, are twin-hulled ocean surveillance ships. Each vessel has a length of 235 feet (ft) (71.6 meters (m)); a beam of 93.6 ft (28.5 m); a maximum draft of 25 ft (7.6 m); and a full load displacement of 3,396 tons (3,451 metric tons). A twin-shaft diesel electric engine provides 3,200 horsepower (hp), which drives two propellers. The USNS IMPECCABLE, also a twin-hulled ocean surveillance ship, has a length of 281.5 ft (85.8 m); a beam of 95.8 ft (29.2 m); a maximum draft of 26 ft (7.9 m); and a full load displacement of 5,368 tons (5,454 metric tons). A twin-shaft diesel electric engine provides 5,000 hp, which drives two propellers. The operational speed of each vessel during sonar activities will be approximately 3.4 miles per hour (mph) (5.6 km per hour (km/hr); 3 knots (kt)) and each vessel's cruising speed outside of sonar activities would be a maximum of approximately 11.5 to 14.9 mph (18.5 to 24.1 km/hr; 10 to 13 kts). During sonar activities, the SURTASS LFA sonar vessels will generally travel in straight lines or in oval-shaped ( i.e., racetrack) patterns depending on the operational scenario. Each vessel also has an observation area on the bridge from where lookouts will monitor for marine mammals before and during LFA sonar activities. When stationed on the bridge of the USNS ABLE, EFFECTIVE, or VICTORIOUS, the lookout's eye level will be approximately 32 ft (9.7 m) above sea level providing an unobstructed view around the entire vessel. For the USNS IMPECCABLE, the lookout's eye level will be approximately 45 ft (13.7 m) above sea level. Notice of Receipt Comments and Responses On October 21, 2016, NMFS published a notice of receipt (NOR) of an application for rulemaking in the Federal Register (81 FR 72782) and requested comments and information from the interested public for 30 days. During the 30-day comment period, which ended on November 21, 2016, NMFS received one comment from an environmental non-governmental organization. This comment stated that the Navy should address several shortcomings in the application such as: (1) Update the information of the impacts of LFA sonar on sensitive federal protected species and their critical habitat; (2) increase the number of offshore biological important areas and expand others to include marine mammal critical habitat; (3) increase current buffer zones to reduce impacts of LFA sonar; (4) update the scientific information of the impact of LFA sonar on marine mammals; (5) provide an analysis of negative effects for information-poor populations; (6) analyze cumulative impacts of LFA sonar, including the synergistic/additive effects of climate change; and (7) include additional mitigation measures to reduce LFA sonar impacts. The Navy addressed impacts to endangered and threatened species and critical habitat in their application, and the Navy and NMFS' Office of Protected Resources Permits and Conservation Division are currently in consultation with NMFS' Office of Protected Resources ESA Interagency Consultation Division. Consistent with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, September 29, 1989), the impacts from past and ongoing anthropogenic activities are reflected in the environmental baseline ( e.g., these impacts are reflected in the density/distribution and status of the species, population size and growth rate, and ambient noise). The reader is also referred to the 2016 DSEIS/SOEIS for more detailed information, including the cumulative impacts and climate change analyses. As noted in the Navy's application, as well as the DSEIS/SOEIS (for which NMFS is a cooperating agency with the Navy for purposes of adopting the DSEIS for this action and in this proposed rule, the number of biologically important areas under consideration have been expanded (commenter noted there are only 22 OBIAs, but there are 28 included in the application and DSEIS/SOEIS). NMFS has addressed the issue of increased buffer zones in previous rulemaking, and it was determined that this was not warranted (see 77 FR 50290, August 20, 2012, Comment 36 Response, and response to comment NRDC-17 of the Navy's 2012 FSEIS/SOEIS for rationale for the additional 1 km buffer). Reanalysis of the matter in this rule confirms this determination. Required buffer zones imposed by NMFS on the Navy's SURTASS LFA sonar include an additional 1 km buffer zone around the Navy's LFA Mitigation Zone and an additional 1 km buffer zone seaward of any OBIA during the time of biological importance. Implementation of the additional 1 km buffer zone will ensure that no marine mammals are exposed to an SPL greater than approximately 174 dB re: 1 μPa, which is below levels for which most marine mammals are anticipated to experience onset of TTS or PTS, and therefore limits potential takes to lower-level Level B behavioral harassment. Lastly, NMFS and Navy evaluated ways to address data-poor scenarios and potential additional mitigation measures as part of the rulemaking process and ongoing adaptive management, which is described in more detail below. The Marine Mammal Commission (MMC) did not submit comments in response to the NOR, but had previously submitted comments to the Navy and NMFS in response to the Navy's DSEIS/OEIS, and stated that these comments would also suffice as their comments on the Navy's application. The MMC made recommendations to use the best available science plus some measure of uncertainty ( e.g., mean plus two standard deviations, mean plus the coefficient of variation, the upper limit of the confidence level) in instances where density data were extrapolated due to data not being available; that the Navy make its Marine Species Density Database (NMSDD) available to the public as soon as possible, specify how density estimates were derived, and what statistic ( e.g., mean, median, maximum) was used when multiple sources are referenced; expressed concern regarding the Navy's use of the single ping equivalent (SPE) metric (discussed in more detail below), and recommended that the Navy either use the SPL or sound exposure level (SEL) metric in assessment of behavioral risk from exposure to SURTASS LFA sonar, or use behavior response metrics and thresholds based on Finneran and Jenkins (2012); recommended that the Navy amend its DSEIS/SOEIS to specify the numbers of marine mammals that could be taken by Level A and B harassment incidental to operating SURTASS LFA sonar, rather than providing the percentages of each stock for such takes; requested further clarification in regard to whether there were zero Level A takes modeled, or if Level A takes were reduced to zero with mitigation applied; and expressed agreement with the proposed expansion of five OBIAs and the addition of six new OBIAs, but requested additional information on the evaluation for determining that other areas did not meet the criteria for designation as OBIAs. Regarding the NMSDD, all data sources that go into the database are cited so they can be obtained. Some of the data sources are proprietary, so the Navy is unable to provide the NMSDD in GIS shapefile format because they only have a license for the Navy. NMFS notes that the single ping equivalent (SPE) has been used in each of the previous rulemakings and NMFS continues to believe the use of this metric is appropriate for assessing behavioral responses for SURTASS LFA sonar because it is a conservative estimate that accounts for the increased potential for behavioral responses due to repeated exposures by adding 5 x log10 (number of pings) to each 1-dB received level (RL) increment, and sums these across all dB levels to determine the dB SPE for each modeled animal ( i.e., SPE is a cumulative metric which accounts for not only the level of exposure but also the duration of exposure). The behavior response data used to derive Finneran and Jenkins (2012) thresholds were from mid-frequency sources, while the data used to derive the behavioral thresholds for SURTASS LFA were specifically from studies using the actual source. Therefore, NMFS feels they are more appropriate to apply to SURTASS LFA sonar. Also, as in previous rulemakings, the proposed rule does not specify the number of marine mammals that may be taken in the proposed locations because these numbers are determined annually through various inputs such as mission location, mission duration, and season of operation. As with previous rulemakings, this proposed rule analyzes a maximum of 12 percent takes by Level B harassment per stock annually, and the Navy will use the 12 percent limit to guide its mission planning and annual LOA applications as described in more detail below. We also note that the analysis for this rulemaking used the updated thresholds per the NMFS 2016 Acoustic Technical Guidance, and based on this analysis, NMFS and the Navy believe that it is unlikely that Level A Harassment takes are likely to occur, and therefore none are proposed to be authorized. Lastly, in regard to OBIAs, we continue to work with the Navy in reviewing and analyzing OBIAs as part of adaptive management. As described in the 2012 rulemaking as well as the Navy's 2016 application and DSEIS/SOEIS, as new information becomes available, areas are re-evaluated to determine if any areas should be added or expanded. NMFS has also evaluated the recommendations in a white paper written by NMFS scientists (discussed in detail below). Description of Marine Mammals in the Area of the Specified Activities One hundred and four (104) currently classified marine mammal species or stocks have confirmed or possible occurrence within potential SURTASS LFA activity areas in certain areas of the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea. Fifteen (15) species of baleen whales (mysticetes), 60 species of toothed whales, dolphins, or porpoises (odontocetes), and 29 species of seals or sea lions (pinnipeds) could be affected by SURTASS LFA sonar activities. Multiple stocks of some species are affected, and independent assessments are conducted to make the necessary findings and determinations for each of these. There are 20 marine mammal species under NMFS' jurisdiction that are listed as endangered or threatened under the Endangered Species Act (ESA; 16 U.S.C. 1531 et seq. ) with confirmed or possible occurrence in potential activity areas for SURTASS LFA sonar. Marine mammal species under NMFS' jurisdiction listed as endangered include: The blue whale ( Balaenoptera musculus ); fin whale ( Balaenoptera physalus ); sei whale ( Balaenoptera borealis ); the Arabian Sea, Cape Verde Islands/Northwest Africa, Central America, and Western North Pacific distinct population segments (DPS) of humpback whale ( Megaptera novaeangliae ); bowhead whale ( Balaena mysticetus ); North Atlantic right whale ( Eubalaena glacialis ); North Pacific right whale ( Eubalaena japonica ); southern right whale ( Eubalaena australis ); Western North Pacific population of gray whale ( Eschrichtius robustus ); sperm whale ( Physeter macrocephalus ); the Cook Inlet stock of beluga whale ( Delphinapterus leucas ); the main Hawaiian Islands Insular DPS of false killer whale ( Psuedorca crassidens ); the Southern Resident population of Killer whale ( Orca orcinus ); the Western DPS of the Steller sea lion ( Eumetopias jubatus ); Mediterranean monk seal ( Monachus monachus ); and Hawaiian monk seal ( Monachus schauinslandi ). Marine mammal species under NMFS' jurisdiction listed as threatened include: The Guadalupe fur seal ( Arctocephalus townsendi ); the Okhotsk ringed seal ( Pusa hispida ochotensis ); the Okhotsk DPS of Pacific bearded seal ( Erignathus barbatus nauticus ); the southern DPS of the spotted seal ( Phoca largha ); and the Mexico DPS of humpback whale ( Megaptera novaeangliae ). Additionally, the Gulf of Mexico subspecies of the Bryde's whale has recently been proposed for listing under the ESA as endangered. The aforementioned threatened and endangered marine mammal species also are depleted under the MMPA. Three of the 104 species or stocks with potential occurrences within possible SURTASS LFA activity areas are considered depleted under the MMPA but are not ESA-listed. They are: The Eastern (Loughlin's) Steller sea lion ( Eumetopias jubatus monteriensis ); the Pribilof Island/Eastern Pacific stock of northern fur seal ( Callorhinus ursinus ); and the arctic ringed seal ( Pusa hispida hispida ). Chinese river dolphins ( Lipotes vexillifer ) and vaquita ( Phocoena sinus ) do not have stocks designated within potential SURTASS LFA sonar operational areas (see Potential SURTASS LFA Operational Areas section). The distribution of the Chinese river dolphin is limited to the main channel of a river section between the cities of Jingzhou and Jiangyin. The vaquita's distribution is restricted to the upper portion of the northern Gulf of California, mostly within the Colorado River delta. Based on the extremely rare occurrence of these species in the Navy's operational areas and coastal standoff range ( i.e., distance of 22 km (13 mi; 12 nmi) from land), take of Chinese river dolphins or vaquita is not considered a reasonable likelihood; therefore these species are not addressed further in this document. The U.S. Fish and Wildlife Service (USFWS) is responsible for managing the following marine mammal species: Southern sea otter ( Enhydra lutris ), polar bear ( Ursus maritimus ), walrus ( Odobenus rosmarus ), west African manatee ( Trichechus senegalensis ), Amazonian manatee ( Trichechus inunguis ), west Indian manatee ( Trichechus manatus ), and dugong ( Dugong dugon ). None of these species occur in geographic areas that would overlap with SURTASS LFA sonar operational areas. Therefore, the Navy has determined that SURTASS LFA sonar activities would have no effect on the endangered or threatened species or the critical habitat of the ESA-listed species under the jurisdiction of the USFWS. These species are not considered further in this notice. Tables 3 through 28 (below) summarize the abundance, status under the ESA, and density estimates of the marine mammal species and stocks that have confirmed or possible occurrence within 26 SURTASS LFA sonar operating areas in the Pacific, Indian, and Atlantic Oceans and Mediterranean Sea. To accurately assess the potential effects of worldwide SURTASS LFA sonar activities, the Navy modeled 26 representative sites based on the Navy's current assessment of current and future requirements or threats. Table 3—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 1, the Sea of Japan [Summer season] Species Stock name 1 Stock abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 5 NA EN Fin whale WNP 9,250 0.0002 EN Sei whale NP 7,000 0.0006 EN Bryde's whale WNP 20,501 0.0006 NL Minke whale WNP “O” Stock 25,049 0.0022 NL North Pacific right whale WNP 922 NA EN Humpback whale WNP 1,328 0.00036 EN Sperm whale NP 102,112 0.00123 EN Harbor porpoise WNP 31,046 0.0190 NL Baird's beaked whale WNP 8,000 0.0029 NL Cuvier's beaked whale WNP 90,725 0.0031 NL Ginkgo-toothed beaked whale NP 22,799 0.0005 NL Hubbs beaked whale NP 22,799 0.0005 NL False killer whale WNP—Pelagic 16,668 0.0036 NL Pygmy killer whale WNP 30,214 0.0021 NL Short-finned pilot whale WNP 53,608 0.0128 NL Risso's dolphin WNP 83,289 0.0097 NL Short-beaked common dolphin WNP 3,286,163 0.0761 NL Killer whale WNP 12,256 0.0001 NL Common bottlenose dolphin WNP 168,791 0.0171 NL Pantropical spotted dolphin WNP 438,064 0.0259 NL Striped dolphin WNP 570,038 0.0111 NL Spinner dolphin WNP 1,015,059 0.00083 NL Pacific white-sided dolphin NP 931,000 0.0082 NL Rough-toothed dolphin WNP 145,729 0.0059 NL Kogia spp WNP 350,553 0.0031 NL Stejneger's beaked whale WNP 8,000 0.0005 NL 1 NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 4—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 2, North Philippine Sea Operational Area [Fall season] Species Stock name 1 Abundance 2 Density (animals/Km 2 ) 3 ESA status 4 Bryde's whale WNP 20,501 0.0006 NL Minke whale WNP “O” Stock 25,049 0.0044 NL North Pacific right whale WNP 922 5 NA EN Blue whale WNP 9,250 .00001 EN Fin whale WNP 9,250 NA EN Humpback whale WNP 1,328 .00089 EN Omura's whale WNP 1,800 .00006 NL Sperm whale NP 102,112 0.00123 EN Common bottlenose dolphin WNP 168,791 0.0146 NL Cuvier's beaked whale WNP 90,725 0.0054 NL Blainville's beaked whale WNP 8,032 0.0005 NL Ginkgo-toothed beaked whale NP 22,799 0.0005 NL Killer whale WNP 12,256 0.00009 NL False killer whale WNP—Pelagic 16,668 0.0029 NL Pygmy killer whale WNP 30,214 0.0021 NL Melon-headed whale WNP 36,770 0.00428 NL Short-finned pilot whale WNP 53,608 0.0153 NL Risso's dolphin WNP 83,289 0.0106 NL Short-beaked common dolphin WNP 3,286,163 0.0562 NL Fraser's dolphin WNP 220,789 0.0069 NL Kogia spp WNP 350,553 0.0031 * Long-beaked common dolphin WNP 279,182 0.1158 NL Longman's beaked whale WNP 4,571 0.00025 NL Pantropical spotted dolphin WNP 438,064 0.0137 NL Striped dolphin WNP 570,038 0.0329 NL Spinner dolphin WNP 1,015,059 0.00083 NL Pacific white-sided dolphin NP 931,000 NA NL Rough-toothed dolphin WNP 145,729 0.0059 NL 1 NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 5—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 3, West Philippine Sea Operational Area [Fall season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 .00001 EN Bryde's whale WNP 20,501 0.0006 NL Minke whale WNP “O” Stock 25,049 0.0033 NL Fin whale WNP 9,250 5 NA EN Humpback whale WNP 1,328 0.00089 EN Omura's whale WNP 1,800 0.00006 NL Sperm whale NP 102,112 0.00123 EN Killer whale WNP 12,256 0.00009 NL Cuvier's beaked whale WNP 90,725 0.0003 NL Blainville`s beaked whale WNP 8,032 0.0005 NL Ginkgo-toothed beaked whale NP 22,799 0.0005 NL False killer whale WNP—Pelagic 16,668 0.0029 NL Pygmy killer whale WNP 30,214 0.0021 NL Melon-headed whale WNP 36,770 0.00428 NL Short-finned pilot whale WNP 53,608 0.0076 NL Risso's dolphin WNP 83,289 0.0106 NL Kogia spp WNP 350,553 0.0017 * Fraser's dolphin WNP 220,789 0.0069 NL Common bottlenose dolphin WNP 168,791 0.0146 NL Deraniyagala's beaked whale NP 22,799 0.0005 NL Pantropical spotted dolphin WNP 438,064 0.0137 NL Striped dolphin WNP 570,038 0.0164 NL Spinner dolphin WNP 1,015,059 0.00083 NL Rough-toothed dolphin WNP 145,729 0.0059 NL Long-beaked common dolphin WNP 279,182 0.1158 NL Longman's beaked whale WNP 4,571 0.00025 NL 1 NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 6—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 4, Offshore Guam [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 NA 5 EN Fin whale WNP 9,250 NA EN Sei whale NP 7,000 NA EN Bryde's whale WNP 20,501 0.0004 NL Minke whale WNP “O” Stock 25,049 NA NL Humpback whale WNP 1,328 NA EN Omura's whale WNP 1,800 0.00004 NL Sperm whale NP 102,112 0.00123 EN Pygmy sperm whale WNP 350,553 0.00291 NL Dwarf sperm whale WNP 350,553 0.00714 NL Cuvier's beaked whale WNP 90,725 0.00079 NL Blainville's beaked whale WNP 8,032 0.001 NL Ginkgo-toothed beaked whale NP 22,799 0.00093 NL Longman's beaked whale WNP 4,571 0.0019 NL Killer whale WNP 12,256 0.00014 NL False killer whale WNP—Pelagic 16,668 0.00111 NL Pygmy killer whale WNP 30,214 0.00014 NL Melon-headed whale NMI 2,455 0.00428 NL Short-finned pilot whale WNP 53,608 0.0051 NL Risso's dolphin WNP 83,289 0.003 NL Deraniyagala's beaked whale NP 22,799 0.00093 NL Fraser's dolphin CNP 16,992 0.0069 NL Common bottlenose dolphin WNP 168,791 0.00245 NL Pantropical spotted dolphin WNP 438,064 0.0226 NL Striped dolphin WNP 570,038 0.00616 NL Spinner dolphin WNP 1,015,059 0.00083 NL Rough-toothed dolphin WNP 145,729 0.0026 NL 1 CNP = central north Pacific; NP = north Pacific; WNP = western north Pacific; NMI = Northern Mariana Islands. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 7—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 5, Sea of Japan [Fall season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Fin whale WNP 9,250 0.0009 EN Bryde's whale WNP 20,501 0.0001 NL Minke whale WNP “O” Stock 25,049 0.0004 NL Minke whale WNP “J” Stock 893 0.00016 NL North Pacific right whale WNP 922 5 NA EN Gray whale WNP 140 0.00001 EN 6 Omura's whale WNP 1,800 0.00001 NL Sperm whale NP 102,112 0.00123 EN Stejneger's beaked whale WNP 8,000 0.0005 NL Baird's beaked whale WNP 8,000 0.0003 NL Cuvier's beaked whale WNP 90,725 0.0031 NL Harbor porpoise WNP 31,046 0.0190 NL False killer whale IA-Pelagic 9,777 0.0027 NL Killer whale WNP 12,256 0.00009 NL Short-finned pilot whale WNP 53,608 0.0014 NL Risso's dolphin IA 83,289 0.0073 NL Short-beaked common dolphin WNP 3,286,163 0.0860 NL Common bottlenose dolphin IA 105,138 0.00077 NL Kogia spp WNP 350,553 0.0017 * Spinner dolphin WNP 1,015,059 0.00083 NL Pacific white-sided dolphin NP 931,000 NA NL Dall's porpoise SOJ 173,638 0.0520 NL Long-beaked common dolphin WNP 279,182 0.1158 NL Rough-toothed dolphin WNP 145,729 0.0026 NL Striped dolphin IA 570,038 0.00584 NL Spotted seal Southern stock 3,500 0.00001 T 1 IA = Inshore Archipelago; NP = north Pacific; SOJ = Sea of Japan; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. 6 Only the western Pacific population of gray whale is endangered under the ESA. Table 8—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 6, East China Sea [Summer season] Species Stock Name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Fin whale ECS 500 0.0002 EN Bryde's whale ECS 137 0.0003 NL Minke whale WNP “O” Stock 25,049 0.0044 NL Minke whale WNP “J” Stock 893 0.0018 NL North Pacific right whale WNP 922 5 NA EN Gray whale WNP 140 NA EN 6 Omura's whale WNP 1,800 0.00003 NL Sperm whale NP 102,112 0.00123 EN Cuvier's beaked whale WNP 90,725 0.0003 NL Blainville's beaked whale WNP 8,032 0.0005 NL Ginkgo-toothed beaked whale NP 22,799 0.0005 NL False killer whale IA-Pelagic 9,777 0.00111 NL Pygmy killer whale WNP 30,214 0.00014 NL Melon-headed whale WNP 36,770 0.00428 NL Short-finned pilot whale WNP 53,608 0.0016 NL Risso's dolphin IA 83,289 0.0106 NL Short-beaked common dolphin WNP 3,286,163 0.0461 NL Fraser's dolphin WNP 220,789 0.00694 NL Common bottlenose dolphin IA 105,138 0.00077 NL Pantropical spotted dolphin WNP 219,032 0.01374 NL Striped dolphin IA 570,038 0.00584 NL Spinner dolphin WNP 1,015,059 0.00083 NL Pacific white-sided dolphin NP 931,000 NA NL Rough-toothed dolphin WNP 145,729 0.0026 NL Killer whale WNP 12,256 0.00009 NL Kogia spp WNP 350,553 0.0017 * Long-beaked common dolphin WNP 279,182 0.1158 NL Longman's beaked whale WNP 4,571 0.00025 NL Spotted seal Southern stock 1,000 0.00001 T 1 ECS = East China Sea; IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. 6 Only the western Pacific population of gray whale is endangered under the ESA. Table 9—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 7, South China Sea [Fall season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Fin whale WNP 9,250 0.0002 EN Bryde's whale WNP 20,501 0.0006 NL Minke whale WNP “O” Stock 25,049 0.0033 NL Minke whale WNP “J” Stock 893 0.0018 NL Humpback whale WNP 1,328 0.00036 EN North Pacific right whale WNP 922 5 NA EN Omura's whale WNP 1,800 0. 00006 NL Gray whale WNP 140 0.00001 EN 6 Sperm whale NP 102,112 0.0012 EN Long-beaked common dolphin WNP 279,182 0.1158 NL Cuvier's beaked whale WNP 90,725 0.0003 NL Blainville's beaked whale WNP 8,032 0.0005 NL Ginkgo-toothed beaked whale NP 22,799 0.0005 NL False killer whale IA-Pelagic 9,777 0.00111 NL Pygmy killer whale WNP 30,214 0.00014 NL Melon-headed whale WNP 36,770 0.00428 NL Short-finned pilot whale WNP 53,608 0.00159 NL Risso's dolphin IA 83,289 0.0106 NL Longman's beaked whale WNP 4,571 0.00025 NL Fraser's dolphin WNP 220,789 0.00694 NL Common bottlenose dolphin IA 105,138 0.00077 NL Pantropical spotted dolphin WNP 219,032 0.01374 NL Striped dolphin IA 570,038 0.00584 NL Spinner dolphin WNP 1,015,059 0.00083 NL Rough-toothed dolphin WNP 145,729 0.0026 NL Deraniyagala's beaked whale NP 22,799 0.0005 NL Killer whale WNP 12,256 0.00009 NL Kogia spp WNP 350,553 0.0017 * 1 IA = Inshore Archipelago; NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. 6 Only the western Pacific population of gray whale is endangered under the ESA. Table 10—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 8, Offshore Japan 25° to 40° N. [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 5 NA EN Fin whale WNP 9,250 0.0001 EN Sei whale NP 7,000 0.00029 EN Bryde's whale WNP 20,501 0.00041 NL Minke whale WNP “O” Stock 25,049 0.0003 NL Humpback whale WNP 1,328 0.00036 EN Sperm whale NP 102,112 0.0022 EN Pygmy sperm whale WNP 350,553 0.0018 NL Dwarf sperm whale WNP 350,553 0.0043 NL Northern right whale dolphin NP 68,000 NA NL Blainville's beaked whale WNP 8,032 0.0007 NL Hubb's beaked whale NP 22,799 0.0005 NL Killer whale WNP 12,296 0.00009 NL Longman's beaked whale WNP 4,571 0.0003 NL Baird's beaked whale WNP 8,000 0.0001 NL Cuvier's beaked whale NP 90,725 0.00374 NL Mesoplodon spp WNP 22,799 0.0005 NL False killer whale WNP-Pelagic 16,668 0.0036 NL Pygmy killer whale WNP 30,214 0.0001 NL Melon-headed whale WNP 36,770 0.0027 NL Short-finned pilot whale WNP 53,608 0.0021 NL Risso's dolphin WNP 83,289 0.0005 NL Short-beaked common dolphin WNP 3,286,163 0.0863 NL Common bottlenose dolphin WNP 168,791 0.00077 NL Pantropical spotted dolphin WNP 438,064 0.0113 NL Striped dolphin WNP 570,038 0.0058 NL Spinner dolphin WNP 1,015,059 0.0019 NL Pacific white-sided dolphin NP 931,000 0.0048 NL Rough-toothed dolphin WNP 145,729 0.0019 NL Stejneger's beaked whale WNP 8,000 0.0005 NL Hawaiian monk seal Hawaii 1,400 0.00001 EN Northern fur seal Western Pacific 503,609 NA NL 1 NP = north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 11—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 9, Offshore Japan 10° to 25° N. [Winter season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 0.00001 EN Bryde's whale WNP 20,501 0.0003 NL Fin whale WNP 9,250 0.00001 EN Humpback whale WNP 1,328 0.00036 EN Omura's whale WNP 1,800 0.00003 NL Sei whale NP 7,000 0.0029 EN Sperm whale NP 102,112 0.00222 EN Pygmy sperm whale WNP 350,553 0.00176 NL Dwarf sperm whale WNP 350,553 0.0043 NL Cuvier's beaked whale WNP 90,725 0.00374 NL False killer whale WNP 16,668 0.00057 NL Melon-headed whale WNP 36,770 0.00267 NL Short-finned pilot whale WNP 53,608 0.00211 NL Risso's dolphin WNP 83,289 0.00046 NL Pygmy killer whale WNP 30,214 0.00006 NL Common bottlenose dolphin WNP 168,791 0.00077 NL Pantropical spotted dolphin WNP 438,064 0.01132 NL Striped dolphin WNP 570,038 0.00584 NL Spinner dolphin WNP 1,015,059 0.00187 NL Rough-toothed dolphin WNP 145,729 0.00185 NL Blainville's beaked whale WNP 8,032 0.0007 NL Deraniyagala's beaked whale NP 22,799 0.00093 NL Fraser's dolphin CNP 16,992 0.00251 NL Ginkgo-toothed beaked whale NP 22,799 0.00093 NL Killer whale WNP 12,256 0.00009 NL Longman's beaked whale WNP 4,571 0.00025 NL 1 NP = north Pacific; CNP = central north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 12—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 10, Northern Hawaii [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale CNP 81 5 NA EN Bryde's whale Hawaii 798 0.0003 NL Common minke whale Hawaii 25,049 NA NL Humpback whale Hawaii DPS 10,103 NA NL Fin whale Hawaii 58 NA EN Sei whale Hawaii 178 NA EN Sperm whale Hawaii 3,354 0.0014 EN Pygmy sperm Hawaii 7,138 0.0029 NL Dwarf sperm whale Hawaii 17,519 0.00714 NL Cuvier's beaked whale Hawaii 1,941 0.0008 NL Blainville's beaked whale Hawaii 2,338 0.001 NL Longman's beaked whale Hawaii 4,571 0.0019 NL Killer whale Hawaii 101 0.00004 NL False killer whale Hawaii-Pelagic 1,540 0.0006 NL False killer whale Main Hawaiian Islands Insular 151 0.0012 EN False killer whale Northwestern Hawaiian Islands 617 0.0013 NL Pygmy killer whale Hawaii 3,433 0.0014 NL Melon-headed whale Hawaiian Islands 5,794 0.0012 NL Melon-headed whale Kohala Resident 447 0.03725 NL Short-finned pilot whale Hawaii 12,422 0.0051 NL Risso's dolphin Hawaii 7,256 0.003 NL Fraser's dolphin Hawaii 16,992 0.0069 NL Common bottlenose dolphin Hawaii pelagic 5,950 0.0025 NL Common bottlenose dolphin Kauai/Niihau 184 0.0001 NL Common bottlenose dolphin 4 Islands 191 0.0001 NL Common bottlenose dolphin Oahu 743 0.0003 NL Common bottlenose dolphin Hawaii Island 128 0.0001 NL Pantropical spotted dolphin Hawaiian Pelagic 15,917 0.0067 NL Pantropical spotted dolphin Hawaiian Island 220 0.0067 NL Pantropical spotted dolphin Oahu 220 0.0067 NL Pantropical spotted dolphin 4 Islands 220 0.0067 NL Striped dolphin Hawaii 20,650 0.0084 NL Spinner dolphin Hawaii Pelagic 3,351 0.0008 NL Spinner dolphin Kauai/Nihau 601 0.007 NL Spinner dolphin Hawaiian Island 631 0.007 NL Spinner dolphin Oahu/4 Islands 355 0.007 NL Spinner dolphin Kure/Midway Atoll 260 0.007 NL Spinner dolphin Pearl and Hermes Reef 300 0.007 NL Rough-toothed dolphin Hawaii 6,288 0.0026 NL Hawaiian monk seal Hawaii 1,112 0.00001 EN 1 CNP = central north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 13—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 11, Southern Hawaii [Fall season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale CNP 81 0.00003 EN Fin whale Hawaii 58 0.00002 EN Bryde's whale Hawaii 798 0.0003 NL Common minke whale Hawaii 25,049 0.0002 NL Humpback whale Hawaii DPS 10,103 0.00089 NL Sei whale Hawaii 178 0.0001 EN Sperm whale Hawaii 3,354 0.0014 EN Pygmy sperm whale Hawaii 7,138 0.0029 NL Blainville's beaked whale Hawaii 2,338 0.001 NL Longman's beaked whale Hawaii 4,571 0.0019 NL Killer whale Hawaii 101 0.00004 NL False killer whale Hawaii-Pelagic 1,540 0.0006 NL False killer whale Main Hawaiian Island Insular 151 0.0012 EN Pygmy killer whale Hawaii 3,433 0.0014 NL Melon-headed whale Hawaiian Islands 5,794 0.0012 NL Melon-headed whale Kohala Resident 447 0.03725 NL Short-finned pilot whale Hawaii 12,422 0.0051 NL Risso's dolphin Hawaii 7,256 0.003 NL Fraser's dolphin Hawaii 16,992 0.0069 NL Common bottlenose dolphin Hawaii Pelagic 5,950 0.00245 NL Common bottlenose dolphin Kauai/Niihau 184 0.0001 NL Common bottlenose dolphin 4 Islands 191 0.0001 NL Common bottlenose dolphin Oahu 743 0.0003 NL Common bottlenose dolphin Hawaii Island 128 0.0001 NL Pantropical spotted dolphin Hawaiian Pelagic 15,917 0.0067 NL Pantropical spotted dolphin Hawaii Island 220 0.0067 NL Pantropical spotted dolphin Oahu 220 0.0067 NL Pantropical spotted dolphin 4 Islands 220 0.0067 NL Striped dolphin Hawaii 20,650 0.0084 NL Spinner dolphin Hawaii Pelagic 3,351 0.0008 NL Spinner dolphin Kauai/Niihau 601 0.007 NL Spinner dolphin Hawaii Island 631 0.007 NL Spinner dolphin Oahu/4 Islands 355 0.007 NL Rough toothed dolphin Hawaii 6,288 0.0026 NL Cuvier's beaked whale Hawaii 1,914 0.0008 NL Deraniyagala's beaked whale NP 22,799 0.00093 NL Dwarf sperm whale Hawaii 17,519 0.00714 NL Hawaiian monk seal Hawaii 1,400 0.00001 EN 1 CNP = central north Pacific; WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 14—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 12, Offshore Southern California [Spring season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale ENP 1,647 0.00011 EN Fin whale CA/OR/WA 3,051 0.00022 EN Sei whale ENP 126 0.00009 EN Bryde's whale ENP 13,000 0.00001 NL Common minke whale CA/OR/WA 478 0.00026 NL Humpback whale Mexico DPS 1,918 0.00121 T Gray whale ENP 20,990 0.03090 NL Gray whale WNP 140 0.00001 EN 5 Sperm whale CA/OR/WA 2,106 0.00337 EN Pygmy sperm whale CA/OR/WA 579 0.00108 NL Stejneger's beaked whale CA/OR/WA 694 0.00065 NL Baird's beaked whale CA/OR/WA 847 0.00046 NL Cuvier's beaked whale CA/OR/WA 6,590 0.00358 NL Blainville's beaked whale CA/OR/WA 694 0.00101 NL Ginkgo-toothed beaked whale CA/OR/WA 694 0.00020 NL Hubbs beaked whale CA/OR/WA 694 0.00086 NL Striped dolphin CA/OR/WA 10,908 0.02592 NL Perrin's beaked whale CA/OR/WA 694 0.00088 NL Pygmy beaked whale CA/OR/WA 694 0.00020 NL Killer whale (offshore) EP 240 0.00030 NL Short-finned pilot whale CA/OR/WA 760 0.00031 NL Risso's dolphin CA/OR/WA 6,272 0.0100 NL Long-beaked common dolphin CA 107,016 0.08591 NL Short-beaked common dolphin CA/OR/WA 411,211 0.95146 NL Common bottlenose dolphin (offshore) CA/OR/WA 1,006 0.01230 NL Pacific white-sided dolphin CA/OR/WA 26,930 0.21549 NL Northern right whale dolphin CA/OR/WA 21,332 0.13352 NL Dall's porpoise CA/OR/WA 42,000 0.02184 NL Guadalupe fur seal Mexico 7,408 0.00387 T Northern fur seal California 14,050 0.01775 NL California sea lion US (Pacific Temperate) 296,750 0.33596 NL Harbor seal California 30,968 0.02033 NL Northern elephant seal CA-Breeding 179,000 0.03222 NL 1 CA/OR/WA = California, Oregon, and Washington; ENP = eastern north Pacific; EP = eastern Pacific; WNP = western north Pacific; SMI = San Miguel Island. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 Only the western Pacific population of gray whale is endangered under the ESA. Table 15—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 13, Western North Atlantic Off Florida [Winter season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Humpback whale West Indies DPS 12,132 0.00004 NL Common minke whale Canadian East Coast 20,174 0.00230 NL North Atlantic right whale WNA 476 0.00002 EN Sperm whale WNA 2,288 0.00083 EN Mesoplodon spp. WNA 7,092 0.00180 NL Kogia spp. WNA 3,785 0.00094 NL Cuvier's beaked whale WNA 6,532 0.00166 NL Common bottlenose dolphin Offshore WNA 77,532 0.04195 NL Common bottlenose dolphin Southern Migratory Coast 9,173 0.00155 NL Common bottlenose dolphin Northern FL Coast 1,219 0.00155 NL Common bottlenose dolphin Central FL Coast 4,895 0.00155 NL Short-finned pilot whale WNA 21,515 0.00616 NL Risso's dolphin WNA 18,250 0.00411 NL False killer whale WNA 442 0.00008 NL Killer whale WNA 67 0.00001 NL Short-beaked common dolphin WNA 173,486 0.00125 NL Pantropical spotted dolphin WNA 3,333 0.00608 NL Striped dolphin WNA 54,807 0.00298 NL Atlantic spotted dolphin WNA 44,715 0.01143 NL Spinner dolphin WNA 262 0.00040 NL Clymene dolphin ( Stenella clymene ) WNA 6,086 0.02522 NL Rough-toothed dolphin WNA 271 0.00069 NL 1 WNA = western north Atlantic. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 16—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 14, Northeastern Atlantic [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale ENA 979 0.00002 EN Fin whale ENA 9,019 0.00100 EN Sei whale Iceland-Denmark Strait 10,300 0.00040 EN Common minke whale Northeast Atlantic 78,572 0.00329 NL Humpback whale Cape Verdes and West Africa DPS 11,572 0.00009 EN Sperm whale ENA 7,785 0.00077 EN Cuvier's beaked whale ENA 6,992 0.00700 NL Gervais' beaked whale ENA 6,992 0.00700 NL Blainville's beaked whale ENA 6,992 0.00700 NL Sowerby's beaked whale ENA 6,992 0.00700 NL Northern bottlenose whale ENA 19,538 0.00260 NL Killer whale Northern Norway 731 0.00001 NL Kogia spp. ENA 3,785 0.00079 NL Long-finned pilot whale ENA 128,093 0.05400 NL Risso's dolphin ENA 18,250 0.00200 NL Short-beaked common dolphin ENA 172,930 0.01000 NL Common bottlenose dolphin ENA 35,780 0.00200 NL Striped dolphin ENA 67,414 0.00150 NL True's beaked whale ENA 6,992 0.00700 NL Atlantic white-sided dolphin ENA 3,904 0.00001 NL White-beaked dolphin ENA 16,536 0.01400 NL Harbor porpoise ENA 375,358 0.07400 NL Harbor seal NW Europe 40,414 0.04000 NL Gray seal NW Europe 116,800 0.00040 NL 1 ENA = eastern north Atlantic. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 17—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 15, Mediterranean Sea [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Fin whale MED 3,583 0.00168 EN Cuvier's beaked whale Alboran Sea 429 0.000108 NL Long-finned pilot whale ENA 21,515 0.0027 NL Risso's dolphin WMED 5,320 0.0011 NL Short-beaked common dolphin WMED 19,428 0.00144 NL Common bottlenose dolphin WMED 1,676 0.00058 NL Sperm whale WMED 396 0.00052 EN Striped dolphin WMED 117,880 0.0436 NL 1 ENA = eastern north Atlantic; MED = Mediterranean; WMED = western Mediterranean. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 18—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 16, Arabian Sea [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale NIND 3,432 0.00004 EN Bryde's whale NIND 9,176 0.0004 NL Common minke whale IND 257,500 0.00920 NL Fin whale IND 1,716 0.00092 EN Humpback whale XAR 200 0.00005 EN Sperm whale NIND 24,446 0.00877 EN Dwarf sperm whale IND 10,541 0.00006 NL Cuvier's beaked whale IND 27,272 0.00308 NL Deraniyagala beaked whale IND 16,867 0.00278 NL Blainville's beaked whale IND 16,867 0.00276 NL Ginkgo-toothed beaked whale IND 16,867 0.00278 NL Longman's beaked whale IND 16,867 0.01193 NL False killer whale IND 144,188 0.00025 NL Pygmy killer whale IND 22,029 0.00141 NL Melon-headed whale IND 64,600 0.00931 NL Short-finned pilot whale IND 268,751 0.03474 NL Risso's dolphin IND 452,125 0.08952 NL Fraser's dolphin IND 151,554 0.00194 NL Common bottlenose dolphin IND 785,585 0.05521 NL Pantropical spotted dolphin IND 736,575 0.00922 NL Striped dolphin IND 674,578 0.15196 NL Spinner dolphin IND 634,108 0.00718 NL Rough-toothed dolphin IND 156,690 0.00075 NL Long-beaked common dolphin IND 1,819,882 0.00013 NL Pygmy sperm whale IND 10,541 0.00002 NL Killer whale IND 12,593 0.00737 NL Indo-Pacific bottlenose dolphin IND 7,850 0.00055 NL 1 IND = Indian Ocean; NIND = northern Indian Ocean; XAR = Stock X Arabian Sea. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 19—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 17, Andaman Sea [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale NIND 3,432 0.00003 EN Bryde's whale NIND 9,176 0.00037 NL Common minke whale IND 257,500 0.00968 NL Fin whale IND 1,716 5 NA EN Omura's whale IND 9,176 0.00037 NL Sperm whale NIND 24,446 0.00107 EN Dwarf sperm whale IND 10,541 0.00006 NL Pygmy sperm whale IND 10,541 0.00001 NL Cuvier's beaked whale IND 27,272 0.00480 NL Blainville's beaked whale IND 16,867 0.00094 NL Ginkgo-toothed beaked whale IND 16,867 0.00097 NL Longman's beaked whale IND 16,867 0.00459 NL Killer whale IND 12,593 0.00730 NL False killer whale IND 144,188 0.00024 NL Fraser's dolphin IND 151,554 0.0018 NL Pygmy killer whale IND 22,029 0.00125 NL Melon-headed whale IND 64,600 0.00878 NL Short-finned pilot whale IND 268,751 0.03543 NL Risso's dolphin IND 452,125 0.09173 NL Long-beaked common dolphin IND 1,819,882 0.00010 NL Common bottlenose dolphin IND 785,585 0.07261 NL Indo-Pacific bottlenose dolphin IND 7,850 0.00073 NL Pantropical spotted dolphin IND 736,575 0.00829 NL Striped dolphin IND 674,578 0.14123 NL Spinner dolphin IND 634,108 0.00701 NL Rough-toothed dolphin IND 156,690 0.00077 NL Deraniyagala beaked whale IND 16,867 0.00097 NL 1 IND = Indian Ocean; NIND = northern Indian Ocean. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 20—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 18, Panama Canal [Winter season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale ENP 1,647 0.00008 EN Bryde's whale ETP 13,000 0.0003 NL Common minke whale ETP 478 0.00031 NL Fin whale ENP 832 5 NA EN Humpback whale Central America DPS 6,000 0.00001 EN Sperm whale ETP 22,700 0.0047 EN Kogia spp. ETP 11,200 0.014 NL Cuvier's beaked whale ETP 20,000 0.00058 NL Blainville's beaked whale ETP 25,300 0.00225 NL Ginkgo-toothed beaked whale ETP 25,300 0.0016 NL Longman's beaked whale ETP 25,300 0.00225 NL Pygmy beaked whale ETP 25,300 0.00225 NL Killer whale ETP 8,500 0.00015 NL False killer whale ETP 39,800 0.0004 NL Pygmy killer whale ETP 38,900 0.0014 NL Melon-headed whale ETP 45,400 0.00313 NL Short-finned pilot whale ETP 160,200 0.01813 NL Risso's dolphin ETP 110,457 0.01781 NL Short-beaked common dolphin ETP 3,127,203 0.005 NL Fraser's dolphin ETP 289,300 0.001 NL Common bottlenose dolphin ETP 335,834 0.0375 NL Pantropical spotted dolphin NEOP 640,000 0.0375 NL Striped dolphin ETP 964,362 0.08125 NL Spinner dolphin Eastern 450,000 0.01875 NL Rough-toothed dolphin ETP 107,633 0.00488 NL Mesoplodon spp. ETP 25,300 0.00225 NL Deraniyagala beaked whale ETP 25,300 0.00225 NL 1 ETP = eastern tropical Pacific; ENP = eastern northern Pacific; NEOP = northeastern offshore Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 21—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 19, Northeastern Australia [Spring season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WSP 9,250 0.00001 EN Fin whale WSP 9,250 0.0002 EN Bryde's whale WSP 20,501 0.0006 NL Common minke whale WSP 25,049 0.0044 EN Humpback whale East Australia DPS 14,500 0.00089 NL Omura's whale WSP 1,800 0.00006 NL Sei whale WSP 7,000 0.0006 EN Sperm whale WSP 102,112 0.00123 EN Cuvier's beaked whale WSP 90,725 0.0054 NL Blainville's beaked whale WSP 8,032 0.0005 NL Ginkgo-toothed beaked whale WSP 22,799 0.0005 NL Longman's beaked whale WSP 4,571 0.00025 NL Kogia spp. WSP 350,553 0.0031 NL Killer whale WSP 12,256 0.00009 NL False killer whale WSP 16,668 0.0029 NL Pygmy killer whale WSP 30,214 0.0021 NL Melon-headed whale WSP 36,770 0.00428 NL Risso's dolphin WSP 83,289 0.0106 NL Short-beaked common dolphin WSP 3,286,163 0.0562 NL Fraser's dolphin WSP 220,789 0.0069 NL Common bottlenose dolphin WSP 168,791 0.0146 NL Pantropical spotted dolphin WSP 438,064 0.0137 NL Striped dolphin WSP 570,038 0.0329 NL Spinner dolphin WSP 1,015,059 0.00083 NL Pilot whales WSP 53,608 0.0153 NL Rough-toothed dolphin WSP 145,729 0.0059 NL 1 GVEA = group V east Australia; WSP = western south Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 22—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 20, Northwestern Australia [Winter season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale SIND 1,657 5 NA EN Fin whale SIND 38,185 0.00001 EN Bryde's whale SIND 13,854 0.00032 NL Antarctic minke whale ANT 90,000 NA NL Common minke whale IND 257,500 NA NL Humpback whale Western Australia DPS 13,640 NA NL Omura's whale IND 13,854 0.00032 NL Sei whale IND 13,854 0.00001 EN Blainville's beaked whale IND 16,867 0.00083 NL Common bottlenose dolphin IND 3,000 0.03630 NL Cuvier's beaked whale IND 76,500 0.00399 NL Dwarf sperm whale IND 10,541 0.00004 NL False killer whale IND 144,188 0.00020 NL Fraser's dolphin IND 151,554 0.00145 NL Killer whale IND 12,593 0.00585 NL Longman's beaked whale IND 16,867 0.00393 NL Melon-headed whale IND 64,600 0.00717 NL Pantropical spotted dolphin IND 736,575 0.00727 NL Pygmy killer whale IND 22,029 0.00100 NL Risso's dolphin IND 452,125 0.07152 NL Rough-toothed dolphin IND 156,690 0.00059 NL Short-finned pilot whale IND 268,751 0.02698 NL Southern bottlenose whale IND 599,300 0.00083 NL Spade-toothed beaked whale IND 16,867 0.00083 NL Sperm whale SIND 24,446 0.00096 EN Spinner dolphin IND 634,108 0.00561 NL Striped dolphin IND 674,578 0.12018 NL 1 ANT = Antarctic; SIND = southern Indian Ocean; IND = Indian Ocean. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 23—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 21, Northeast of Japan [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNP 9,250 5 NA EN Common minke whale WNP “O” 25,049 0.0022 NL Fin whale WNP 9,250 0.0002 EN Humpback whale WNP 1,328 0.00050 EN North Pacific right whale WNP 922 0.00001 EN Sei whale NP 7,000 0.00029 EN Western North Pacific gray whale Western DPS 140 0.00001 EN Baird's beaked whale WNP 8,000 0.0029 NL Cuvier's beaked whale WNP 90,725 0.0054 NL Dall's porpoise WNP 173,638 0.0650 NL Killer whale WNP 12,256 0.0036 NL Pacific white-sided dolphin NP 931,000 0.0048 NL Short-beaked common dolphin WNP 3,286,163 0.0863 NL Sperm whale NP 102,112 0.0022 EN Stejneger's beaked whale WNP 8,000 0.0005 NL Northern fur seal Western Pacific 503,609 0.01378 NL Ribbon seal NP 61,100 0.0452 NL Spotted seal Bering Sea DPS 460,268 0.2770 NL Steller sea lion West-Asian stock and Western DPS 62,218 0.00001 EN 1 IND = Indian Ocean; NP = northern Pacific; WNP = western north Pacific; ENP = eastern north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Table 24—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 22, Southern Gulf of Alaska [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale ENP 1,647 0.00051 EN Common minke whale AK 1,233 0.0006 NL Eastern North Pacific gray whale ENP 20,990 0.00019 NL Fin whale AK/NE Pacific 1,368 0.00049 EN Humpback whale Hawaii DPS Mexico DPS WNP DPS 10,103 0.00050 NL T EN North Pacific right whale ENP 31 0.00003 EN Sei whale ENP 126 0.00007 EN Baird's beaked whale AK 847 0.0004 NL Cuvier's beaked whale AK 6,590 0.00245 NL Dall's porpoise AK 173,638 0.07214 NL Killer whale ENP AK resident 2,347 0.005 NL Killer whale ENP Gulf of AK, Aleutian Islands, and Bering Sea Transient 587 0.00021 NL Pacific white-sided dolphin NP 26,880 0.0208 NL Sperm whale NP 102,112 0.00127 EN Stejneger's beaked whale AK 694 0.00084 NL Northern elephant seal California Breeding 179,000 0.0038 NL Northern fur seal EP 648,534 0.03211 NL Ribbon seal AK 184,000 0.00001 NL Steller sea lion Eastern DPS 60,131 0.01085 NL Steller sea lion Western DPS 49,497 0.01085 EN 1 IND = Indian Ocean; NP = northern Pacific; ENP = eastern north Pacific; AK = Alaska. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 25—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 23, Southern Norwegian Basin [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale ENA 979 0.00001 EN Common minke whale Northeast Atlantic 78,572 0.03206 NL Fin whale North-West Norway 6,409 0.00157 EN Humpback whale Cape Verdes-NW Africa DPS West Indies DPS 11,572 0.00009 EN NL Sei whale Iceland-Denmark Strait 10,300 0.00001 EN Atlantic white-sided dolphin ENA 3,904 0.00001 NL Cuvier's beaked whale ENA 6,992 0.011 NL Harbor porpoise ENA 375,358 0.074 NL Killer whale Northern Norway 731 0.00001 NL Long-finned pilot whale ENA 128,093 0.054 NL Northern bottlenose dolphin ENA 19,538 0.0026 NL Sowerby's beaked whale ENA 6,992 0.011 NL Sperm whale ENA 7,785 0.0049 EN White-beaked dolphin ENA 16,536 0.011 NL Hooded seal West Ice 84,020 0.00811 NL 1 ENA = eastern north Atlantic. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 26—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 24, Western North Atlantic off Virginia/Maryland [Summer season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Common minke whale Canadian East Coast 20,741 0.00013 NL Fin whale WNA 1,618 0.00075 EN Humpback whale West Indies DPS 12,312 0.00006 NL North Atlantic right whale WNA 476 <0.00001 NL Atlantic spotted dolphin WNA 44,715 0.09630 NL Clymene dolphin WNA 6,086 0.01424 NL Common bottlenose dolphin Offshore WNA 77,532 0.04241 NL Northern Migratory Coastal 11,548 0.00236 NL Southern Migratory Coastal 9,173 0.00236 NL Cuvier's beaked whale WNA 6,532 0.00878 NL False killer whale WNA 442 0.00008 NL Killer whale WNA 67 0.00001 NL Kogia spp WNA 3,785 0.00079 NL Mesoplodon spp WNA 7,092 0.00954 NL Pantropical spotted dolphin WNA 3,333 0.00515 NL Risso's dolphin WNA 18,250 0.02202 NL Rough-toothed dolphin WNA 271 0.00060 NL Short-beaked common dolphin WNA 173,486 0.07284 NL Short-finned pilot whale WNA 21,515 0.02215 NL Sperm whale WNA 2,288 0.01274 EN Spinner dolphin WNA 262 0.00034 NL Striped dolphin WNA 54,807 0.13345 NL 1 WNA = western north Atlantic. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 27—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 25, Labrador Sea [Winter season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Blue whale WNA 440 0.00002 EN Common minke whale Canadian East Coast 20,741 0.00013 NL Fin whale Canadian East Coast 1,352 0.00005 EN Humpback whale West Indies DPS 12,312 0.00019 NL North Atlantic right whale WNA 476 <0.00001 EN Sei whale Labrador Sea 965 0.00002 EN Atlantic white-sided dolphin Labrador Sea 24,422 0.00200 NL Harbor porpoise Newfoundland 3,326 0.00160 NL Killer whale WNA 67 0.00001 NL Long-finned pilot whale Canadian East Coast 6,134 0.00370 NL Northern bottlenose dolphin Davis Strait 50 0.00001 NL Short-beaked common dolphin WNA 173,486 0.00100 NL Sowerby's beaked whale WNA 50 0.00001 NL Sperm whale WNA 2,288 0.00127 EN White-beaked dolphin Canadian East Coast 15,625 0.00077 NL Arctic ringed seal Arctic 787,000 0.07300 NL Harp seal WNA 7,411,000 0.07043 NL Hooded seal WNA 592,100 0.0081 NL 1 WNA = western north Atlantic. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. Table 28—Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Mission Area 26, Sea of Okhotsk [Spring season] Species Stock name 1 Abundance 2 Density (animals/km 2 ) 3 ESA status 4 Bowhead whale Okhotsk Sea 247 0.00001 EN Common minke whale WNP “O” WNP “J” 25,049 893 0.01727 0.00062 NL EN Fin whale WNP 9,250 0.0002 EN Humpback whale WNP DPS 1,328 0.00089 EN North Pacific right whale WNP 922 5 NA EN Western North Pacific gray whale Western DPS 140 NA EN Baird's beaked whale WNP 8,000 0.0015 NL Beluga whale Okhotsk Sea 12,226 0.0071 NL Cuvier's beaked whale WNP 90,725 0.0054 Nl Dall's porpoise WNP dalli-trype 111,402 0.18031 NL WNP truei-type 101,173 0.16375 NL Harbor porpoise WNP 31,046 0.0190 NL Killer whale Okhotsk-Kamchatka-Western Aleutians Transient 12,256 0.0036 NL Pacific white-sided dolphin NP 931,000 0.0048 NL Sperm whale NP 102,112 0.0022 EN Northern fur seal Western Pacific 503,609 0.08031 NL Okhotsk ringed seal Okhotsk 676,000 0.23881 T Pacific bearded seal Okhotsk DPS 200,000 0.01174 T Ribbon seal Sea of Okhotsk 124,000 0.0904 NL Spotted seal Sea of Okhotsk DPS 180,000 0.2770 NL Steller sea lion Western DPS 82,516 0.02189 EN 1 WNP = western north Pacific. 2 Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table. 3 Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. 4 ESA Status: EN = Endangered; T = Threatened; NL = Not Listed. 5 NA in the Density column indicates that although the stock or DPS occurs in that mission area, it is not expected to occur during the season modeled. Information on how the density and stock/abundance estimates were derived for the selected mission sites is in the Navy's application. These data are derived from the best available, published source documentation, and provide general area information for each mission area with species-specific information on the animals that could occur in that area, including estimates for their stock abundance and density. The Navy developed the abundance and density estimates by first using estimates from line-transect surveys that occurred in or near each of the 26 model sites ( e.g., Barlow, 2006). However, density estimates require more sophisticated sampling and analysis and were not always available for each species at all sites. When density estimates were not available from a survey in the operating area, the Navy extrapolated density estimates from a region with similar oceanographic characteristics to that operating area. For example, the eastern tropical Pacific has been extensively surveyed and provides a comprehensive understanding of marine mammals in temperate oceanic waters (Ferguson and Barlow, 2001, 2003). Density estimates for some mission areas/model sites were also derived from the Navy's Marine Species Density Database (DoN, 2016b). In addition, density estimates are usually not available for rare marine mammal species or for those that have been newly defined ( e.g., the Deraniyagala's beaked whale). For these species, the lowest density estimate of 0.0001 animals/square kilometer (0.0001 animals/km 2 ) was used in the take analysis to reflect the low probability of occurrence in a specific SURTASS LFA sonar mission area. Further, the Navy pooled density estimates for species of the same genus if sufficient data are not available to compute a density for individual species or the species are difficult to distinguish at sea, which is often the case for pilot whales and beaked whales, as well as the pygmy and dwarf sperm whales. Density estimates are available for these species groups rather than the individual species. The Navy provides detailed descriptions of the distribution, abundance, diving behavior, life history, and hearing vocalization information for each affected marine mammal species with confirmed or possible occurrence within SURTASS LFA sonar operational areas in section 4 (pages 4-1 through 4-71) of the application, which is available online at http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications ). Although not repeated in this document, NMFS has reviewed these data, determined them to be the best available scientific information for the proposed rulemaking, and considers this information part of the administrative record for this action. Additional information is available in NMFS' Marine Mammal Stock Assessment Reports, which may be viewed at http://www.nmfs.noaa.gov/pr/sars/species.htm. NMFS refers the public to Table 3-2 (pages 3-9 through 3-36) of the Navy's application for literature references associated with abundance and density estimates presented in these tables. Brief Background on Sound, Marine Mammal Hearing, and Vocalization Underwater Sound An understanding of the basic properties of underwater sound is necessary to comprehend many of the concepts and analyses presented in this document. Sound is a wave of pressure variations propagating through a medium (for the sonar considered in this proposed rulemaking, the medium is seawater). Pressure variations are created by compressing and relaxing the medium. Sound measurements can be expressed in two forms: Intensity and pressure. Acoustic intensity is the average rate of energy transmitted through a unit area in a specified direction and is expressed in watts per square meter (W/m 2 ). Acoustic intensity is rarely measured directly, it is derived from ratios of pressures; the standard reference pressure for underwater sound is 1 μPa (Richardson et al., 1995). Acousticians have adopted a logarithmic scale for sound intensities, which is denoted in dB. The logarithmic nature of the scale means that each 10 dB increase is a ten-fold increase in power ( e.g., 20 dB is a 100-fold increase, 30 dB is a 1,000-fold increase). Humans perceive a 10-dB increase in noise as a doubling of sound level, or a 10-dB decrease in noise as a halving of sound level. Sound pressure level or SPL implies a decibel measure and a reference pressure that is used as the denominator of the ratio. Sound frequency is measured in cycles per second, referred to as Hertz (Hz), and is analogous to musical pitch; high-pitched sounds contain high frequencies and low-pitched sounds contain low frequencies. Natural sounds in the ocean span a large range of frequencies: From earthquake noise at five Hz to harbor porpoise clicks at 150,000 Hz (150 kilohertz (kHz)). These sounds are so low or so high in pitch that humans cannot even hear them; acousticians call these infrasonic (typically below 20 Hz, which is considered the low frequency bound of human hearing) and ultrasonic (typically above 20,000 Hz, which is considered the upper bound of human hearing) sounds, respectively. A single sound may be made up of multiple frequencies. Sounds made up of only a small range of frequencies are called narrowband, and sounds with a broad range of frequencies are called broadband. Explosives are an example of a broadband sound source and tactical military sonars are an example of a narrowband sound source. Metrics Used in This Document This section includes a brief explanation of the sound measurements frequently used in the discussions of acoustic effects in this document. Sound Pressure Level Sound pressure level (SPL) is expressed as the ratio of a measured sound pressure and a reference level. The commonly used reference pressure level in underwater acoustics is 1 μPa, and the units for SPLs are decibels (dB) re: 1 μPa. SPL (in dB) = 20 log (pressure/reference pressure). SPL is an instantaneous measurement and can be expressed as the peak, the peak-peak (p-p), or the root mean square (rms). SPL does not directly take the duration of exposure to a sound into account, though it should be noted that the duration over which the root mean square pressure is averaged since it influences the result. Root mean square pressure, which is the square root of the arithmetic average of the squared instantaneous pressure values (Urick, 1983), is typically used in discussions of behavioral effects of sounds on vertebrates in part because behavioral effects, which often result from auditory cues, may be better expressed through averaged units than by peak pressures. All references to SPL in this document refer to the root mean square unless otherwise noted. Cumulative Sound Exposure Level Sound exposure level (SEL; represented as dB re 1 μPa 2 -s) represents the total energy contained within a pulse, and considers both exposure level and duration of exposure. The NMFS 2016 Acoustic Technical Guidance builds upon the foundation provided by Southall et al. (2007), while incorporating new information available since development of that work ( e.g., Finneran, 2015). Southall et al. (2007) recommended specific thresholds under the dual metric approach ( i.e., peak SPL (SPL pk ) and cumulative SEL (SEL cum )), and that marine mammals be divided into hearing groups based on measured or estimated hearing ranges. The premise of the dual criteria approach is that, while there is no definitive answer to the question of which acoustic metric is most appropriate for assessing the potential for auditory injury, both the exposure level and duration of received signals are important to an understanding of the potential for injury. Therefore, peak SPL is used to define a pressure criterion above which auditory injury is predicted to occur, regardless of exposure duration ( i.e., any single exposure at or above this level is considered to cause auditory injury), and the SEL cum metric is used to account for the total energy received over the specified duration of sound exposure ( i.e., metric accounts for both received level and duration of exposure) (Southall et al., 2007; NMFS, 2016). As SPL pk is applicable to impulsive noise, it is not applicable to SURTASS LFA sonar and is not discussed further here. Note that SEL cum acoustic thresholds also incorporate marine mammal auditory weighting functions. NMFS (2016) recommends 24 hours as a maximum accumulation period relative to SEL cum thresholds. For further discussion of auditory weighting functions and their application or metrics associated with evaluating noise-induced hearing loss, please see NMFS (2016). Table 29 displays auditory impact thresholds provided by NMFS (2016). Table 29—TTS and PTS Onset Thresholds for Non-Impulsive Sounds 1 Hearing group Cumulative sound exposure level for TTS 1 (dB) Cumulative sound exposure level for PTS 1 (dB) Low-frequency cetaceans 179 199 Mid-frequency cetaceans 178 198 High-frequency cetaceans 153 173 Phoicid pinnipeds (PW) (Underwater) 181 201 Otariid pinnipeds (OW) (Underwater) 199 219 1 Referenced to 1 μPa 2 s; weighted according to appropriate auditory weighting function. Single Ping Equivalent (SPE) To model potential behavioral impacts to marine animals from exposure to SURTASS LFA sonar sound, the Navy has developed a methodology to estimate the total exposure of modeled animals exposed to multiple pings over an extended period of time. The Navy's acoustic model analyzes the following components: (1) The LFA sonar source modeled as a point source, with an effective source level (SL) in dB re: 1 μPa at 1 m (SPL); (2) a 60-sec duration signal; and (3) a beam pattern that is correct for the number and spacing of the individual projectors (source elements). This source model, when combined with the three-dimensional transmission loss (TL) field generated by the Parabolic Equation (PE) acoustic propagation model, defines the received level (RL) (in SPL) sound field surrounding the source for a 60-sec LFA sonar signal ( i.e., the SPE metric accounts for received level and exposure from multiple pings). To estimate the total exposure of animals exposed to multiple pings, the Navy models the RLs for each modeled location and any computer-simulated marine mammals (animats) within the location, records the exposure history of each animat, and generates a SPE value. Thus, the Navy can model the SURTASS LFA sound field, providing a four-dimensional (position and time) representation of a sound pressure field within the marine environment and estimates of an animal's exposure to sound over a period of 24 hours. Figure 2 shows the Navy calculation that converts SPL values to SPE values in order to estimate impacts to marine mammals from SURTASS LFA sonar transmissions. For a more detailed explanation of the SPE calculations, NMFS refers the public to Appendix B of the Navy's 2016 DSEIS/SOEIS. EP27AP17.001 Marine Mammal Hearing Cetaceans have an auditory anatomy that follows the basic mammalian pattern, with some changes to adapt to the demands of hearing in the sea. The typical mammalian ear is divided into an outer ear, middle ear, and inner ear. The outer ear is separated from the inner ear by a tympanic membrane, or eardrum. In terrestrial mammals, the outer ear, eardrum, and middle ear transmit airborne sound to the inner ear, where the sound waves are propagated through the cochlear fluid. Since the impedance of water ( i.e., the product of density and sound speed) is close to that of the tissues of a cetacean, the outer ear is not required to transduce sound energy as it does when sound waves travel from air to fluid (inner ear). Sound waves traveling through the inner ear cause the basilar membrane to vibrate. Specialized cells, called hair cells, respond to the vibration and produce nerve pulses that are transmitted to the central nervous system. Acoustic energy causes the basilar membrane in the cochlea to vibrate. Sensory cells at different positions along the basilar membrane are excited by different frequencies of sound (Pickles, 1998). When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different frequencies of sound. Based on available behavioral data, audiograms derived using auditory evoked potential (AEP) techniques, anatomical modeling, and other data, Southall et al. (2007) designated “functional hearing groups” for marine mammals and estimated the lower and upper frequencies of functional hearing ( i.e., the frequencies that the species can actually hear) of these groups as follows: • Low frequency (LF) cetaceans (13 species of mysticetes): Southall et al. (2007) estimates that functional hearing occurs between approximately seven Hz and 22 kHz; • Mid-frequency (MF) cetaceans (32 species of dolphins, six species of larger toothed whales, and 19 species of beaked and bottlenose whales): Southall et al. (2007) estimates that functional hearing occurs between approximately 150 Hz and 160 kHz; • High frequency (HF) cetaceans (eight species of true porpoises, six species of river dolphins, Kogia, the franciscana, and four species of cephalorhynchid s ): Southall et al. (2007) estimates that functional hearing occurs between approximately 200 Hz and 180 kHz. • Pinnipeds in Water: Southall et al. (2007) estimates that functional hearing occurs between approximately 75 Hz and 75 kHz, with the greatest sensitivity between approximately 700 Hz and 20 kHz. In August 2016 NMFS released its Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2016 Acoustic Technical Guidance), which modified the hearing groups proposed in Southall et al. (2007) in the following ways: • Division of pinnipeds into phocids in water (PW) and otariids in water (OW) hearing groups; and • Re-Categorization of two species of dolphins (hourglass [ Lagenorhynchus cruiger ] and Peale's [ L. australis ]) from mid-frequency (MF) to high-frequency (HF) hearing group. Therefore, under the new NMFS 2016 Acoustic Technical Guidance, there are five marine mammal hearing group categories, with associated generalized hearing ranges as shown in Table 30 (note that animals are less sensitive to sounds at the outer edge of their generalized hearing range and most sensitive to sounds of frequencies within a smaller range somewhere in the middle of their functional hearing range). Table 30—Marine Mammal Hearing Groups [NMFS, 2016] Hearing group Generalized hearing range 1 Low-frequency (LF) cetaceans (baleen whales) 7 Hz to 35 kHz. Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) 150 Hz to 160 kHz. High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, cephalorhynchid, Lagenorhynchus cruciger & L. australis ) 275 Hz to 160 kHz. Phocid pinnipeds underwater (PW) (true seals) 50 Hz to 86 kHz. Otariid pinnipeds underwater (OW) (sea lions and fur seals) 60 Hz to 39 kHz. 1 Represents the generalized hearing range for the entire group as a composite ( i.e., all species within the group), where individual species' hearing ranges are typically not as broad. Generalized hearing range chosen based on ~65 dB threshold from normalized composite audiogram, with the exception for lower limits for LF cetaceans (Southall et al. 2007) and PW pinniped (approximation). Marine Mammal Hearing Groups and LFA Sonar Baleen (mysticete) whales (members of the LF hearing group) have inner ears that appear to be specialized for low-frequency hearing. Conversely, most odontocetes ( i.e., dolphins and porpoises) have inner ears that are specialized to hear mid and high frequencies. Pinnipeds, which lack the highly specialized active biosonar systems of odontocetes, have inner ears that are specialized to hear a broad range of frequencies in water (Southall et al., 2007). Based on an extensive suite of reported laboratory measurements (DoN, 2001, Ketten, 1997, Southall et al., 2007), the LFA sound source is below the range of best hearing sensitivity for MF and HF odontocete and pinnipeds in water hearing specialists (Clark and Southall, 2009). Marine Mammal Vocalization Marine mammal vocalizations often extend both above and below the range of human hearing (higher than 20 kHz and lower than 20 Hz; Research Council, 2003). Measured data on the hearing abilities of cetaceans are sparse, particularly for the larger cetaceans such as the baleen whales. The auditory thresholds of some of the smaller odontocetes have been determined in captivity. It is generally believed that cetaceans should at least be sensitive to the frequencies of their own vocalizations. Comparisons of the anatomy of cetacean inner ears and models of the structural properties and the response to vibrations of the ear's components in different species provide an indication of likely sensitivity to various sound frequencies. Thus, the ears of small toothed whales are optimized for receiving high-frequency sound, while baleen whale inner ears are best suited for low frequencies, including to infrasonic frequencies (Ketten, 1992; 1997; 1998). Baleen whale ( i.e., mysticete) vocalizations are composed primarily of frequencies below one kHz, and some contain fundamental frequencies as low as 16 Hz (Watkins et al., 1987; Richardson et al., 1995; Rivers, 1997; Moore et al., 1998; Stafford et al., 1999; Wartzok and Ketten, 1999) but can be as high as 24 kHz (humpback whale; Au et al., 2006). Clark and Ellison (2004) suggested that baleen whales use low frequency sounds not only for long-range communication, but also as a simple form of echo ranging, using echoes to navigate and orient relative to physical features of the ocean. Information on auditory function in mysticetes is limited. Sensitivity to low frequency sound by baleen whales has been inferred from observed vocalization frequencies, observed reactions to playback of sounds, and anatomical analyses of the auditory system. Although there is apparently much variation, the source levels of most baleen whale vocalizations lie in the range of 150-190 dB re: 1 μPa at 1 m. Low-frequency vocalizations made by baleen whales and their corresponding auditory anatomy suggest that they have good low-frequency hearing (Ketten, 2000), although specific data on sensitivity, frequency or intensity discrimination, or localization abilities are lacking. Marine mammals, like all mammals, have typical U-shaped audiograms that begin with relatively low sensitivity (high threshold) at some specified low frequency with increased sensitivity (low threshold) to a species-specific optimum followed by a generally steep rise at higher frequencies (high threshold) (Fay, 1988). Toothed whales ( i.e., odontocetes) produce a wide variety of sounds, which include species-specific broadband “clicks” with peak energy between 10 and 200 kHz, individually variable “burst pulse” click trains, and constant frequency or frequency-modulated (FM) whistles ranging from 4 to 16 kHz (Wartzok and Ketten, 1999). The general consensus is that the tonal vocalizations (whistles) produced by toothed whales play an important role in maintaining contact between dispersed individuals, while broadband clicks are used during echolocation (Wartzok and Ketten, 1999). Burst pulses have also been strongly implicated in communication, with some scientists suggesting that they play an important role in agonistic encounters (McCowan and Reiss, 1995), while others have proposed that they represent “emotive” signals in a broader sense, possibly representing graded communication signals (Herzing, 1996). Sperm whales, however, are known to produce only clicks, which are used for both communication and echolocation (Whitehead, 2003). Most of the energy of toothed whales' social vocalizations is concentrated near 10 kHz, with source levels for whistles as high as 100-180 dB re 1 μPa at 1 m (Richardson et al., 1995). No odontocete has been shown audiometrically to have acute hearing (less than 80 dB re 1 μPa at 1 m) below 500 Hz (DoN, 2001; Ketten, 1998). Sperm whales produce clicks, which may be used to echolocate (Mullins et al., 1988), with a frequency range from less than 100 Hz to 30 kHz and source levels up to 230 dB re 1 μPa at 1 m or greater (Mohl et al., 2000). Potential Effects of the Specified Activity on Marine Mammals and Their Habitat This section includes a summary and discussion of the ways that components of the specified activities may impact marine mammals and their habitat. The Estimated Take of Marine Mammals section later in this document will include a quantitative analysis of the maximum percentage of the affected stocks that are expected to be taken by the SURTASS LFA activities, but enumeration of takes of individuals is completed annually when the Navy submits their application for LOAs for that year's mission areas. The Negligible Impact Analysis and Determination section will consider the content of this section, the Estimated Take of Marine Mammals section, and the Proposed Mitigation section to draw conclusions regarding the likely impacts of these activities on the reproductive success or survivorship of individuals and how those impacts on individuals are likely to impact marine mammal species or stocks. The Navy has requested authorization for the incidental take of marine mammals that may result from upcoming use of SURTASS LFA sonar by a maximum of four U.S. Naval ships in certain areas of the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea. In addition to the use of LFA and HF/M3 sonar, the Navy has analyzed the potential impact of ship strike to marine mammals from SURTASS LFA sonar activities, and, in consultation with NMFS as a cooperating agency for the SURTASS LFA sonar 2016 DSEIS/SOEIS, has determined that take of marine mammals incidental to this non-acoustic component of the Navy's operations is not reasonably likely to occur. Therefore, the Navy has not requested authorization for take of marine mammals that might occur incidental to vessel ship strike. In this document, NMFS analyzes the potential effects on marine mammals from exposure to LFA and HF/M3 sonar, but also includes some additional analysis of the potential impacts from vessel operations. NMFS' analysis of potential impacts from SURTASS LFA activities is outlined in the next section. NMFS will focus qualitatively on the different ways that SURTASS LFA sonar activities may affect marine mammals (some of which may not be classifiedas takes). Then, in the Estimated Take of Marine Mammals section, NMFS will relate the potential effects to marine mammals from SURTASS LFA sonar activities to the MMPA definitions of take, including Level A and Level B Harassment. The potential effects to marine mammals described in the following sections do not take into consideration the proposed mitigation and related monitoring measures described later in this document (see the Proposed Mitigation section) which, as noted, are designed to effect the least practicable adverse impact on affected marine mammals species and stocks. Potential Effects of Exposure to SURTASS LFA Sonar Activities The potential effects of sound from the proposed activities associated with SURTASS LFA sonar might include one or more of the following: Behavioral changes, masking, non-auditory injury ( i.e., gas bubble formation/rectified diffusion), and noise-induced loss of hearing sensitivity (more commonly called threshold shift). NMFS discusses these potential effects in more detail below. The effects of underwater noise on marine mammals are highly variable, and one can categorize the effects as follows (Richardson et al., 1995; Nowacek et al., 2007; Southall et al., 2007): (1) The noise may be too weak to be heard at the location of the animal ( i.e., lower than the prevailing ambient noise level, the hearing threshold of the animal at relevant frequencies, or both); (2) The noise may be audible but not strong enough to elicit any overt behavioral response; (3) The noise may elicit behavioral reactions of variable conspicuousness and variable relevance to the well-being of the animal. These can range from temporary alert responses to active avoidance reactions such as vacating an area at least until the noise event ceases, but potentially for longer periods of time; (4) Upon repeated exposure, a marine mammal may exhibit diminishing responsiveness (habituation), disturbance effects may persist, or disturbance effects could increase (sensitization, or becoming more sensitive to exposure). Persistent disturbance and sensitization are more likely with sounds that are highly variable in characteristics, infrequent, and unpredictable in occurrence, and associated with situations that the animal perceives as a threat (animals are not likely to be exposed enough to SURTASS LFA sonar to exhibit habituation or increased sensitization, due to the fact that SURTASS LFA sonar is a mobile source operating in open water, and animals are likely to move away and/or would not be receiving pings in the way that small resident populations would receive with a stationary source); (5) Any anthropogenic (human-made) noise that is strong enough to be heard has the potential to reduce the ability of a marine mammal to hear natural sounds at similar frequencies (masking), including calls from conspecifics ( i.e., an organism of the same species), and underwater environmental sounds such as surf noise; (6) If mammals remain in an area because it is important for feeding, breeding, or some other biologically important purpose even though there is a chronic exposure to noise, it is possible that there could be noise-induced physiological stress. This might in turn have negative effects on the well-being or reproduction of the animals involved; and (7) Very strong sounds have the potential to cause temporary or permanent reduction in hearing sensitivity, also known as threshold shift. In terrestrial mammals and presumably marine mammals, received sound levels must far exceed the animal's hearing threshold for there to be any temporary threshold shift (TTS) in its hearing ability. For transient sounds, the sound level necessary to cause TTS is inversely related to the duration of the sound. Received sound levels must be even higher for there to be the possibility of permanent hearing impairment. In addition, intense acoustic or explosive events (not relevant for this proposed activity) may cause trauma to tissues associated with organs vital for hearing, sound production, respiration and other functions. This trauma may include minor to severe hemorrhage. Direct Physiological Effects Threshold Shift (Noise-Induced Loss of Hearing) When animals exhibit reduced hearing sensitivity within their auditory range ( i.e., sounds must be louder for an animal to detect them) following exposure to a sufficiently intense sound or a less intense sound for a sufficient duration, it is referred to as a noise-induced threshold shift (TS). An animal can experience a temporary threshold shift (TTS) and/or permanent threshold shift (PTS). TTS can last from minutes or hours to days ( i.e., there is recovery back to baseline/pre-exposure levels), can occur within a specific frequency range ( i.e., an animal might only have a temporary loss of hearing sensitivity within a limited frequency band of its auditory range), and can be of varying amounts (for example, an animal's hearing sensitivity might be reduced by only six dB or reduced by 30 dB). PTS is permanent ( i.e., there is incomplete recovery back to baseline/pre-exposure levels), but also can occur in a specific frequency range and amount as mentioned above for TTS. The following physiological mechanisms are thought to play a role [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%3A2017-08066. Public record. Not legal advice.